Trifluoromethylpyridines of formula (Ia) and (Ib) are new. In cpds. (Ia), R2a = CF3, and R2b = halo; in cpds. (Ib), R2a = halo, and R2b = CF3; R1 = NH2 or NHNH2; in (Ib), R1 may also be Cl or Br; R3 = 1-6Calkyl, 1-6Calkenyl or 1-6Calkynyl (all opt. substd. by 1-6 halo), 3-6C cycloalkyl (opt. substd. by 1-3 of 1-3C alkyl), 1-6C alkyl substd. by CN, COOH, 1-6C alkoxycarbonyl, 1-4C alkoxy-2-4C alkoxycarbonyl, CONH2, CONH-1-4C alkyl, CON(1-4C alkyl)2,CONH-2-4C alkenyl, CONH-3-4C alkynyl or CON(1-4C alkyl) (3-4C alkenyl or alkynyl); 2-6C alkyl substd. by 1-4C alkoxy or 3-6C-( alpha -alkylalkylidene)iminoxy, 3-oxetanyl, cyclopropylmethyl, 1-6C alkylamino, di(1-6C alkyl)amino; 1-6C alkylideneimino or alpha -(1-4C alkyl)-2-6C alkylideneimino; and halo = F, Cl, Br or I.