Abstract. For a finite l-group G, let ram t (G) denote the minimal integer such that G can be realized as the Galois group of a tamely ramified extension of Q ramified only at ram t (G) finite primes. We study the upper bound of ram t (G) and give an improvement of the result of Plans. We also give the best bound of ram t (G) for all 3-groups G of order less than or equal to 3 5 .