diff --git a/README.md b/README.md
index 83167bfee..5132332a5 100644
--- a/README.md
+++ b/README.md
@@ -69,11 +69,14 @@ prerequisites for building yosys:
 		graphviz xdot pkg-config python3 libboost-system-dev \
 		libboost-python-dev libboost-filesystem-dev
 
-Similarily, on Mac OS X MacPorts or Homebrew can be used to install dependencies:
+Similarily, on Mac OS X Homebrew can be used to install dependencies:
 
 	$ brew tap Homebrew/bundle && brew bundle
+
+or MacPorts:
+
 	$ sudo port install bison flex readline gawk libffi \
-		git graphviz pkgconfig python36 boost
+		git graphviz pkgconfig python36 boost tcl
 
 On FreeBSD use the following command to install all prerequisites: