diff --git a/changelog.md b/changelog.md
index 3c02c4e..37ba480 100644
--- a/changelog.md
+++ b/changelog.md
@@ -2,6 +2,7 @@
 
  - **bug**: fixed comparisons breaking in STM when using namespaces (see [#90](https://github.com/mixer/etcd3/issues/90))
  - **feat**: allow retrieving lock lease IDs (see [#75](https://github.com/mixer/etcd3/issues/75))
+ - **bug**: fixed using `lease.put` in transactions not applying the lease to the target key (see [#92](https://github.com/mixer/etcd3/issues/92))
 
 ## 0.2.12 2019-07-03
 
diff --git a/src/builder.ts b/src/builder.ts
index a26d091..a2278c4 100644
--- a/src/builder.ts
+++ b/src/builder.ts
@@ -24,7 +24,7 @@ export interface ICompareTarget {
 }
 
 export interface IOperation {
-  op(): RPC.IRequestOp;
+  op(): Promise<RPC.IRequestOp>;
 }
 
 /**
@@ -121,8 +121,8 @@ export abstract class RangeBuilder<T> extends PromiseWrap<T> implements IOperati
   /**
    * Returns the request op for this builder, used in transactions.
    */
-  public op(): RPC.IRequestOp {
-    return { request_range: this.namespace.applyToRequest(this.request) };
+  public op(): Promise<RPC.IRequestOp> {
+    return Promise.resolve({ request_range: this.namespace.applyToRequest(this.request) });
   }
 }
 
@@ -416,10 +416,10 @@ export class DeleteBuilder extends PromiseWrap<RPC.IDeleteRangeResponse> {
   /**
    * Returns the request op for this builder, used in transactions.
    */
-  public op(): RPC.IRequestOp {
-    return {
+  public op(): Promise<RPC.IRequestOp> {
+    return Promise.resolve({
       request_delete_range: this.namespace.applyToRequest(this.request),
-    };
+    });
   }
 
   /**
@@ -435,6 +435,7 @@ export class DeleteBuilder extends PromiseWrap<RPC.IDeleteRangeResponse> {
  */
 export class PutBuilder extends PromiseWrap<RPC.IPutResponse> {
   private request: RPC.IPutRequest = {};
+  private leaseFilter?: string | number | Promise<string | number>;
   private callOptions: grpc.CallOptions | undefined;
 
   constructor(
@@ -458,8 +459,8 @@ export class PutBuilder extends PromiseWrap<RPC.IPutResponse> {
    * Sets the lease value to use for storing the key. You usually don't
    * need to use this directly, use `client.lease()` instead!
    */
-  public lease(lease: number | string): this {
-    this.request.lease = lease;
+  public lease(lease: number | string | Promise<string | number>): this {
+    this.leaseFilter = lease;
     return this;
   }
 
@@ -502,14 +503,16 @@ export class PutBuilder extends PromiseWrap<RPC.IPutResponse> {
   /**
    * exec runs the put request.
    */
-  public exec(): Promise<RPC.IPutResponse> {
+  public async exec(): Promise<RPC.IPutResponse> {
+    await this.applyLease();
     return this.kv.put(this.namespace.applyToRequest(this.request), this.callOptions);
   }
 
   /**
    * Returns the request op for this builder, used in transactions.
    */
-  public op(): RPC.IRequestOp {
+  public async op(): Promise<RPC.IRequestOp> {
+    await this.applyLease();
     return { request_put: this.namespace.applyToRequest(this.request) };
   }
 
@@ -519,6 +522,18 @@ export class PutBuilder extends PromiseWrap<RPC.IPutResponse> {
   protected createPromise(): Promise<RPC.IPutResponse> {
     return this.exec();
   }
+
+  private async applyLease() {
+    if (!this.leaseFilter) {
+      return;
+    }
+
+    if (typeof this.leaseFilter === 'number' || typeof this.leaseFilter === 'string') {
+      this.request.lease = this.leaseFilter;
+    }
+
+    this.request.lease = await this.leaseFilter;
+  }
 }
 
 /**
@@ -544,7 +559,11 @@ export class PutBuilder extends PromiseWrap<RPC.IPutResponse> {
  * ```
  */
 export class ComparatorBuilder {
-  private request: RPC.ITxnRequest = {};
+  private request: {
+    compare: Promise<RPC.ICompare>[];
+    success: Promise<RPC.IRequestOp>[];
+    failure: Promise<RPC.IRequestOp>[];
+  } = { compare: [], success: [], failure: [] };
   private callOptions: grpc.CallOptions | undefined;
 
   constructor(private readonly kv: RPC.KVClient, private readonly namespace: NSApplicator) {}
@@ -573,13 +592,14 @@ export class ComparatorBuilder {
       value = toBuffer(<string | Buffer>value);
     }
 
-    this.request.compare = this.request.compare || [];
-    this.request.compare.push({
-      key: this.namespace.applyKey(toBuffer(key)),
-      result: comparator[cmp],
-      target: RPC.CompareTarget[column],
-      [compareTarget[column]]: value,
-    });
+    this.request.compare.push(
+      Promise.resolve({
+        key: this.namespace.applyKey(toBuffer(key)),
+        result: comparator[cmp],
+        target: RPC.CompareTarget[column],
+        [compareTarget[column]]: value,
+      }),
+    );
     return this;
   }
 
@@ -604,20 +624,27 @@ export class ComparatorBuilder {
   /**
    * Runs the generated transaction and returns its result.
    */
-  public commit(): Promise<RPC.ITxnResponse> {
-    return this.kv.txn(this.request, this.callOptions);
+  public async commit(): Promise<RPC.ITxnResponse> {
+    return this.kv.txn(
+      {
+        compare: await Promise.all(this.request.compare),
+        failure: await Promise.all(this.request.failure),
+        success: await Promise.all(this.request.success),
+      },
+      this.callOptions,
+    );
   }
 
   /**
    * Low-level method to add
    */
-  public mapOperations(ops: (RPC.IRequestOp | IOperation)[]): RPC.IRequestOp[] {
+  public mapOperations(ops: (RPC.IRequestOp | IOperation)[]) {
     return ops.map(op => {
       if (typeof (<IOperation>op).op === 'function') {
         return (<IOperation>op).op();
       }
 
-      return <RPC.IRequestOp>op;
+      return Promise.resolve(<RPC.IRequestOp>op);
     });
   }
 }
diff --git a/src/lease.ts b/src/lease.ts
index 37533b0..53b388c 100644
--- a/src/lease.ts
+++ b/src/lease.ts
@@ -33,19 +33,13 @@ class LeaseClientWrapper implements RPC.ICallable<Host> {
   ) {}
 
   public exec(service: keyof typeof RPC.Services, method: string, payload: any): Promise<any> {
-    return this.lease.leaseID
-      .then(throwIfError)
-      .then(lease => {
-        payload.lease = lease;
-        return this.pool.exec(service, method, payload);
-      })
-      .catch(err => {
-        if (err instanceof EtcdLeaseInvalidError) {
-          this.lease.emitLoss(err);
-        }
+    return this.pool.exec(service, method, payload).catch(err => {
+      if (err instanceof EtcdLeaseInvalidError) {
+        this.lease.emitLoss(err);
+      }
 
-        throw err;
-      });
+      throw err;
+    });
   }
 
   public markFailed(host: Host): void {
@@ -172,7 +166,7 @@ export class Lease extends EventEmitter {
       new RPC.KVClient(new LeaseClientWrapper(this.pool, <any>this)),
       this.namespace,
       key,
-    );
+    ).lease(this.grant());
   }
 
   /**
diff --git a/test/lease.test.ts b/test/lease.test.ts
index c76d6e9..f4d47c9 100644
--- a/test/lease.test.ts
+++ b/test/lease.test.ts
@@ -55,6 +55,20 @@ describe('lease()', () => {
     expect(await client.get('leased').buffer()).to.be.null;
   });
 
+  it('attaches leases through transactions', async () => {
+    lease = client.lease(100);
+    await lease.put('leased').value('foo');
+
+    const result = await client
+      .if('foo1', 'Value', '==', 'bar1')
+      .then(lease.put('leased').value('foo'))
+      .commit();
+    expect(result.succeeded).to.equal(true, 'expected to have completed transaction');
+    expect((await client.get('leased').exec()).kvs[0].lease).to.equal(await lease.grant());
+    await lease.revoke();
+    expect(await client.get('leased').buffer()).to.be.null;
+  });
+
   it('runs immediate keepalives', async () => {
     lease = client.lease(100);
     expect(await lease.keepaliveOnce()).to.containSubset({