diff --git a/packages/apollo-codegen-swift/src/__tests__/__snapshots__/codeGeneration.ts.snap b/packages/apollo-codegen-swift/src/__tests__/__snapshots__/codeGeneration.ts.snap
index 206285d4cb..f9a94e2f26 100644
--- a/packages/apollo-codegen-swift/src/__tests__/__snapshots__/codeGeneration.ts.snap
+++ b/packages/apollo-codegen-swift/src/__tests__/__snapshots__/codeGeneration.ts.snap
@@ -819,7 +819,9 @@ exports[`Swift code generation #structDeclarationForFragment() should generate a
   /// The friends of the character, or an empty list if they have none
   public var friends: [Friend?]? {
     get {
-      return (resultMap[\\"friends\\"] as? [ResultMap?]).flatMap { (value: [ResultMap?]) -> [Friend?] in value.map { (value: ResultMap?) -> Friend? in value.flatMap { (value: ResultMap) -> Friend in Friend(unsafeResultMap: value) } } }
+      return (resultMap[\\"friends\\"] as? [ResultMap?]).flatMap { (value: [ResultMap?]) -> [Friend?] in value.map { (value: ResultMap?) -> Friend? in value.flatMap { (value: ResultMap) -> Friend in Friend(unsafeResultMap: value) } } }.filter({
+        Friend.possibleTypes.contains($0.__typename)
+      })
     }
     set {
       resultMap.updateValue(newValue.flatMap { (value: [Friend?]) -> [ResultMap?] in value.map { (value: Friend?) -> ResultMap? in value.flatMap { (value: Friend) -> ResultMap in value.resultMap } } }, forKey: \\"friends\\")
@@ -967,7 +969,9 @@ exports[`Swift code generation #structDeclarationForSelectionSet() should genera
   /// The friends of the character, or an empty list if they have none
   public var friends: [Friend?]? {
     get {
-      return (resultMap[\\"friends\\"] as? [ResultMap?]).flatMap { (value: [ResultMap?]) -> [Friend?] in value.map { (value: ResultMap?) -> Friend? in value.flatMap { (value: ResultMap) -> Friend in Friend(unsafeResultMap: value) } } }
+      return (resultMap[\\"friends\\"] as? [ResultMap?]).flatMap { (value: [ResultMap?]) -> [Friend?] in value.map { (value: ResultMap?) -> Friend? in value.flatMap { (value: ResultMap) -> Friend in Friend(unsafeResultMap: value) } } }.filter({
+        Friend.possibleTypes.contains($0.__typename)
+      })
     }
     set {
       resultMap.updateValue(newValue.flatMap { (value: [Friend?]) -> [ResultMap?] in value.map { (value: Friend?) -> ResultMap? in value.flatMap { (value: Friend) -> ResultMap in value.resultMap } } }, forKey: \\"friends\\")
diff --git a/packages/apollo-codegen-swift/src/codeGeneration.ts b/packages/apollo-codegen-swift/src/codeGeneration.ts
index 00ac8dfb92..2a1584feb2 100644
--- a/packages/apollo-codegen-swift/src/codeGeneration.ts
+++ b/packages/apollo-codegen-swift/src/codeGeneration.ts
@@ -647,7 +647,15 @@ export class SwiftAPIGenerator extends SwiftGenerator<CompilerContext> {
                 expression,
                 "ResultMap",
                 structName
-              )}`
+              )}.filter`
+            );
+            this.withinBlock(
+              () =>
+                this.printOnNewline(
+                  `${structName}.possibleTypes.contains($0.__typename)`
+                ),
+              "({",
+              "})"
             );
           });
           this.printOnNewline("set");