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