Dynamics of flowering in the two grapevine cvs Matrouh Aswad and Black Rose growing under Nobaria conditions were investigated  during 2000 and 2001 seasons.             The obtained results showed that percentage of flowering per day  in grapevine cv. Matrouh Aswad increased gradually reaching its  maximum in the third and seventh days in both seasons after which a sharp reduction occurred in the subsequent days. The maximum percentage of flowering per day in grapevine cv. Black Rose was presented in the sixth day in the first season and fourth day in the second one. The period of cluster flowering for Matrough Aswad was  7-9 days and for Black Rose was 7-8 days during the two seasons. Percentages of flowering per hour in both grapevine cvs were low at 8A.M then increased sharply attaining its maximum at 13 P.M. then  tended to reduce at 14 P.M.