diff --git a/R/zzz.R b/R/zzz.R
new file mode 100644
index 0000000..e96cecf
--- /dev/null
+++ b/R/zzz.R
@@ -0,0 +1,15 @@
+.onAttach <- function(libname, pkgname) {
+  packageStartupMessage(
+    "
+    The pccc package implements PCCC version 2 [Feudtner et.al. (2014) https://doi.org/10.1186/1471-2431-14-199].
+
+    PCCC version 3 [Feinstein et.al. (2024) https://doi.org/10.1001/jamanetworkopen.2024.20579]
+    has been implimented in another R package: medicalcoder [https://CRAN.R-project.org/package=medicalcoder]
+
+    An improved implementation of PCCC version 2 has also been implemented in medicalcoder.
+
+    Details and examples on transitioning from the pccc package to medicalcoder can be found here:
+    https://www.peteredewitt.com/medicalcoder/articles/transition-pccc-to-medicalcoder.html
+    "
+  )
+}