diff --git a/Makefile b/Makefile
index d6929b5a3..533e2f16f 100644
--- a/Makefile
+++ b/Makefile
@@ -242,7 +242,14 @@ $(PARSO_LIBS): $(CPYTHONLIB)
 
 
 $(CLAPACK): $(CPYTHONLIB)
-	make -C CLAPACK
+	ifdef PYODIDE_PACKAGES
+		echo "Skipping BLAS/LAPACK build due to PYODIDE_PACKAGES being defined."
+		echo "Build it manually with make -C CLAPACK if needed."
+		touch $(CLAPACK)
+	else
+		make -C CLAPACK
+	endif
+
 
 
 build/packages.json: $(CLAPACK) FORCE
diff --git a/docs/building_from_sources.md b/docs/building_from_sources.md
index cd475b363..078fad156 100644
--- a/docs/building_from_sources.md
+++ b/docs/building_from_sources.md
@@ -21,3 +21,6 @@ exactly; in particular they are case sensitive.
 To build a minimal version of pyodide, set `PYODIDE_PACKAGES="micropip"`. The
 micropip and package is generally always included for any non empty value of
 `PYODIDE_PACKAGES`.
+
+If scipy is included in `PYODIDE_PACKAGES`, BLAS/LAPACK must be manually built
+first with `make -c CLAPACK`.