diff --git a/matlab/@dynSeries/plus.m b/matlab/@dynSeries/plus.m
index 9d6482c8f648772a3ae59d5cc6b357f4a1d24373..d60d51d6a433deace8ebd81b06a0d20c7ff8fd0e 100644
--- a/matlab/@dynSeries/plus.m
+++ b/matlab/@dynSeries/plus.m
@@ -40,7 +40,7 @@ function A = plus(B,C)
 % along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
 
 % AUTHOR(S) stephane DOT adjemian AT univ DASH lemans DOT fr
-
+[B, C] = align(B, C);
 if ~isequal(B.vobs,C.vobs) && ~(isequal(B.vobs,1) || isequal(C.vobs,1))
     error(['dynSeries::plus: Cannot add ' inputname(1) ' and ' inputname(2) ' (wrong number of variables)!'])
 else