diff --git a/lib/query-builder.js b/lib/query-builder.js
index faa7f0a..09f8692 100644
--- a/lib/query-builder.js
+++ b/lib/query-builder.js
@@ -113,7 +113,7 @@ function buildQuery (query, parentResult) {
 }
 
 // get keys to reuse on merge results
-function buildQuerySelection (selection, parent, wrap = true) {
+function buildQuerySelection (selection, parent, wrap = true, fragment = undefined) {
   if (!(selection && selection.length > 0)) {
     return { selection: '', keys: [] }
   }
@@ -132,7 +132,7 @@ function buildQuerySelection (selection, parent, wrap = true) {
       fields.add(toQuerySelection(keyField))
       keys.set('key' + keyId(k), k)
     } else if (selection[i].selection) {
-      fields.add(buildQuerySelection(selection[i].selection, null, selection[i].wrap).selection)
+      fields.add(buildQuerySelection(selection[i].selection, null, selection[i].wrap, selection[i].fragment).selection)
     } else if (selection[i].nested) {
       fields.add(selection[i].parentField)
       for (const nested of selection[i].nested.values()) {
@@ -182,7 +182,7 @@ function buildQuerySelection (selection, parent, wrap = true) {
     }
   }
 
-  const qselection = wrap ? `{ ${Array.from(fields).join(' ')} }` : Array.from(fields).join(' ')
+  const qselection = wrap ? `${fragment ? `... on ${fragment} ` : ''}{ ${Array.from(fields).join(' ')} }` : Array.from(fields).join(' ')
   return { selection: qselection, keys: Array.from(keys.values()) }
 }
 
diff --git a/lib/query-lookup.js b/lib/query-lookup.js
index 0a8216c..35e85f7 100644
--- a/lib/query-lookup.js
+++ b/lib/query-lookup.js
@@ -28,6 +28,7 @@ const { mergeMaps, collectNodeArgs, collectPlainArgs, pathJoin } = require('./ut
  */
 function collectQueries ({
   subgraphName, queryFieldNode, path = '', fieldId, parent, args,
+  fragmentFieldTypeName,
   // references
   types, fields, aliases,
   // root: collect root queries
@@ -85,6 +86,7 @@ function collectQueries ({
     field,
     fieldId,
     queryFieldNode,
+
     // TODO maybe parent and root are redundant
     parent,
     root,
@@ -104,8 +106,9 @@ function collectQueries ({
     return { queries, deferreds, order }
   }
 
-  const fieldTypeName = field?.typeName
+  const fieldTypeName = fragmentFieldTypeName ?? field?.typeName
   // const fieldType = field && types[fieldTypeName]
+  const isUnionTypeType = field.type.src.kind === 'UNION'
 
   for (let i = 0; i < queryFieldSelections.length; ++i) {
     const querySelection = queryFieldSelections[i]
@@ -115,6 +118,7 @@ function collectQueries ({
         ? context.info.fragments[querySelection.name.value]
         : querySelection
 
+      const fragmentFieldTypeName = isUnionTypeType ? fragment.typeCondition.name.value : undefined
       // TODO if !field - shouldn't happen
       const nested = collectNestedQueries({
         context,
@@ -124,12 +128,17 @@ function collectQueries ({
         queryNode,
         querySelection: fragment,
         types,
+        fragmentFieldTypeName,
         fields
       })
 
       // unwrap fragment as selection
       for (const n of nested.queries.values()) {
-        queryNode.query.selection.push({ selection: n.query.selection, wrap: false })
+        queryNode.query.selection.push({
+          selection: n.query.selection,
+          wrap: fragmentFieldTypeName !== undefined,
+          fragment: fragmentFieldTypeName
+        })
       }
       collectDeferredQueries(queryNode, nested, deferreds)
 
@@ -161,7 +170,7 @@ function collectQueries ({
 
       context.logger.debug(`deferred query for ${cpath} > ${selectionFieldName} on ${subgraphName}`)
 
-      const alias = aliases[fieldId]
+      const alias = aliases && aliases[fieldId]
       if (alias && nested) {
         nesting({
           selectionFieldName,
@@ -258,7 +267,8 @@ function collectNestedQueries ({
   types,
   fields,
   aliases,
-  alias
+  alias,
+  fragmentFieldTypeName
 }) {
   context.logger.debug({ fieldId, path }, 'query lookup, nested')
   const a = alias ? Object.values(alias)[0] : null
@@ -274,7 +284,8 @@ function collectNestedQueries ({
     types,
     fields,
     aliases,
-    typeName: a?.type
+    typeName: a?.type,
+    fragmentFieldTypeName
   })
 }