diff --git a/go.mod b/go.mod
index 3a6943e..eede542 100644
--- a/go.mod
+++ b/go.mod
@@ -6,6 +6,7 @@ require (
 	github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc // indirect
 	github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf // indirect
 	github.com/aws/aws-sdk-go v1.16.23
+	github.com/blang/semver v3.5.1+incompatible
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fatih/color v1.7.0
 	github.com/ghodss/yaml v1.0.0
diff --git a/go.sum b/go.sum
index 7ddc201..e1bc504 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,8 @@ github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf h1:qet1QNfXsQxTZq
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/aws/aws-sdk-go v1.16.23 h1:MwBOBeez0XEFVh6DCc888X+nHVBCjUDLnnWXSGGWUgM=
 github.com/aws/aws-sdk-go v1.16.23/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
+github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdnnjpJbkM4JQ=
+github.com/blang/semver v3.5.1+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
diff --git a/iamy.go b/iamy.go
index 0814e13..a17ac47 100644
--- a/iamy.go
+++ b/iamy.go
@@ -5,14 +5,20 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"regexp"
 
+	"github.com/blang/semver"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
+const versionTooOldError = `Your version of IAMy (%s) is out of date compared to what the local
+project expects. You should upgrade to %s to use this project.`
+
 var (
-	Version    string = "dev"
-	defaultDir string
-	dryRun     *bool
+	Version         string = "dev"
+	defaultDir      string
+	dryRun          *bool
+	versionFileName string = ".iamy-version"
 )
 
 type logWriter struct{ *log.Logger }
@@ -61,6 +67,8 @@ func main() {
 		log.SetOutput(ioutil.Discard)
 	}
 
+	performVersionChecks()
+
 	switch cmd {
 	case push.FullCommand():
 		PushCommand(ui, PushCommandInput{
@@ -87,3 +95,29 @@ func init() {
 	}
 	defaultDir = filepath.Clean(dir)
 }
+
+func performVersionChecks() {
+	currentIAMyVersion, _ := semver.Make(Version)
+	log.Printf("current version is %s", currentIAMyVersion)
+
+	if _, err := os.Stat(versionFileName); !os.IsNotExist(err) {
+		log.Printf("%s found", versionFileName)
+		fileBytes, _ := ioutil.ReadFile(versionFileName)
+		fileContents := string(fileBytes)
+
+		if fileContents != "" {
+			re := regexp.MustCompile(`\d\.\d+\.\d(\+\w+)?`)
+			match := re.FindStringSubmatch(fileContents)
+			localDesiredVersion, _ := semver.Make(match[0])
+			log.Printf("local project wants version %s", localDesiredVersion)
+
+			// We don't want to notify users if the `Version` is "dev" as it's not
+			// actually too old. It could be that they are running non-released
+			// versions.
+			if Version != "dev" && currentIAMyVersion.LE(localDesiredVersion) {
+				fmt.Printf(versionTooOldError, currentIAMyVersion, localDesiredVersion)
+				os.Exit(1)
+			}
+		}
+	}
+}