Abstract. Let E be an elliptic curve over Q with L-function L E (s). We use the random matrix model of Katz and Sarnak to develop a heuristic for the frequency of vanishing of the twisted L-functions L E (1, χ), as χ runs over the Dirichlet characters of order 3 (cubic twists). The heuristic suggests that the number of cubic twists of conductor less than X for which L E (1, χ) vanishes is asymptotic to b E X 1/2 log e E X for some constants b E , e E depending only on E. We also compute explicitely the conjecture of Keating and Snaith about the moments of the special values L E (1, χ) in the family of cubic twists. Finally, we present experimental data which is consistent with the conjectures for the moments and for the vanishing in the family of cubic twists of L E (s).