We show that every finite abelian group occurs as the group of rational points of an ordinary abelian variety over
F
2
\mathbb {F}_2
,
F
3
\mathbb {F}_3
and
F
5
\mathbb {F}_5
. We produce partial results for abelian varieties over a general finite fieldĀ
F
q
\mathbb {F}_q
. In particular, we show that certain abelian groups cannot occur as groups of rational points of abelian varieties over
F
q
\mathbb {F}_q
when
q
q
is large. Finally, we show that every finite cyclic group arises as the group of rational points of infinitely many simple abelian varieties overĀ
F
2
\mathbb {F}_2
.