diff --git a/fetch/fetch.go b/fetch/fetch.go
index 21dd80e..adf5f49 100644
--- a/fetch/fetch.go
+++ b/fetch/fetch.go
@@ -73,16 +73,10 @@ func FetchPackages(goModPath string, goSumPath string, goMod2NixPath string, dep
 		caches = append(caches, buildGoCache)
 	}
 
-	// // Parse require
-	// require := make(map[string]module.Version)
-	// for _, req := range mod.Require {
-	// 	require[req.Mod.Path] = req.Mod
-	// }
-
 	// Map repos -> replacement repo
 	replace := make(map[string]string)
 	for _, repl := range mod.Replace {
-		replace[repl.Old.Path] = repl.New.Path
+		replace[repl.New.Path] = repl.Old.Path
 	}
 
 	log.WithFields(log.Fields{
@@ -111,12 +105,12 @@ func FetchPackages(goModPath string, goSumPath string, goMod2NixPath string, dep
 	log.WithFields(log.Fields{
 		"numJobs": numJobs,
 	}).Info("Queuing jobs")
-	for goPackagePath, sumVersion := range sumVersions {
+	for importPath, sumVersion := range sumVersions {
 		// Check for replacement path (only original goPackagePath is recorded in go.sum)
-		importPath := goPackagePath
+		goPackagePath := importPath
 		v, ok := replace[goPackagePath]
 		if ok {
-			importPath = v
+			goPackagePath = v
 		}
 
 		jobs <- &packageJob{
@@ -251,6 +245,12 @@ func fetchPackage(caches []map[string]*types.Package, importPath string, goPacka
 		return nil, err
 	}
 
+	vendorPath := ""
+	if importPath != goPackagePath {
+		importPathPrefix, _, _ := module.SplitPathVersion(importPath)
+		vendorPath = importPathPrefix
+	}
+
 	return &types.Package{
 		GoPackagePath: goPackagePath,
 		URL:           repoRoot.Repo,
@@ -260,6 +260,7 @@ func fetchPackage(caches []map[string]*types.Package, importPath string, goPacka
 		// It's also used to construct the vendor directory in the Nix build
 		SumVersion: sumVersion,
 		RelPath:    relPath,
+		VendorPath: vendorPath,
 	}, nil
 
 }
diff --git a/formats/gomod2nix/gomod2nix.go b/formats/gomod2nix/gomod2nix.go
index f48fb71..1210bda 100644
--- a/formats/gomod2nix/gomod2nix.go
+++ b/formats/gomod2nix/gomod2nix.go
@@ -18,6 +18,7 @@ type fetchInfo struct {
 type packageT struct {
 	SumVersion string     `toml:"sumVersion"`
 	RelPath    string     `toml:"relPath"`
+	VendorPath string     `toml:"vendorPath"`
 	Fetch      *fetchInfo `toml:"fetch"`
 }
 
@@ -26,6 +27,7 @@ func Marshal(pkgs []*types.Package) ([]byte, error) {
 
 	for _, pkg := range pkgs {
 		result[pkg.GoPackagePath] = &packageT{
+			VendorPath: pkg.VendorPath,
 			SumVersion: pkg.SumVersion,
 			RelPath:    pkg.RelPath,
 			Fetch: &fetchInfo{
@@ -75,6 +77,7 @@ func LoadGomod2Nix(filePath string) map[string]*types.Package {
 			Sha256:        v.Fetch.Sha256,
 			SumVersion:    v.SumVersion,
 			RelPath:       v.RelPath,
+			VendorPath:    v.VendorPath,
 		}
 	}
 
diff --git a/types/types.go b/types/types.go
index a844b66..6aad1fc 100644
--- a/types/types.go
+++ b/types/types.go
@@ -7,4 +7,5 @@ type Package struct {
 	Sha256        string
 	SumVersion    string
 	RelPath       string
+	VendorPath    string
 }