From ethyl 1-aryl-2-methyl-4-(4-nitrophenyl)pyrrole-3-carboxylates new 1-aryl-2-methyl-4-(4-nitrophenyl)pyrrolderivatives wer prepared. These compounds and some previously reported 1,4- and 1,5-diarylpyrroles were subjected to in vitro antimicrobial screenings. Namely some 1-aryl-2-methyl-4-(4-nitrophenyl)pyrrole-3-carboxylic acids and its 5-chloroderivatives are the most potent. The results obtained are discussed on the basis of structure-activity relationships.