diff --git a/ChangeLog.d/8726.txt b/ChangeLog.d/8726.txt
new file mode 100644
index 0000000000..c1e5a40158
--- /dev/null
+++ b/ChangeLog.d/8726.txt
@@ -0,0 +1,2 @@
+Features
+   * Add partial platform support for z/OS.
diff --git a/library/entropy_poll.c b/library/entropy_poll.c
index de2e0387a0..bd21e2d226 100644
--- a/library/entropy_poll.c
+++ b/library/entropy_poll.c
@@ -29,7 +29,7 @@
 
 #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
     !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \
-    !defined(__HAIKU__) && !defined(__midipix__)
+    !defined(__HAIKU__) && !defined(__midipix__) && !defined(__MVS__)
 #error \
     "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in mbedtls_config.h"
 #endif