diff --git a/CHANGELOG b/CHANGELOG
index dd560536..dd72373d 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,4 @@
+02.01.20 Fix KeyError in allele_merge
 30.07.19 v1.0.1; update changelog and increment version for edits on this date (see #164)
 30.07.19 Fix to display of liability scale gencov, h2 in rg results log (see #162)
 30.07.19 Update munge to use pandas option for gzip output (see #142)
diff --git a/munge_sumstats.py b/munge_sumstats.py
index a683e886..b84e98c9 100755
--- a/munge_sumstats.py
+++ b/munge_sumstats.py
@@ -442,7 +442,7 @@ def allele_merge(dat, alleles, log):
         raise ValueError(
             'All SNPs have alleles that do not match --merge-alleles.')
 
-    dat.loc[~jj, [i for i in dat.columns if i != 'SNP']] = float('nan')
+    dat.loc[~jj.astype('bool'), [i for i in dat.columns if i != 'SNP']] = float('nan')
     dat.drop(['MA'], axis=1, inplace=True)
     return dat