In the current work, new thiazolyl pyrazoline derivatives (1-22) were synthesized and evaluated for their antifungal effects against pathogenic yeasts and molds using a broth microdilution assay. Ames assay was carried out to determine the genotoxicity of the most effective antifungal derivatives. The cytotoxicity of the compounds (1-22) was also investigated against A549 human lung adenocarcinoma and NIH/3T3 mouse embryonic fibroblast cells. Among these derivatives, 2-[5-(4-fluoropheny1)-3-(5-methylthiophen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(4-methylsulfonylphenyl)thiazole (18) can be identified as the most promising anticandidal derivative due to its notable inhibitory effect on Candida zeylanoides with a MIC value of 250 mu g/mL when compared with ketoconazole (MIC = 250 mu g/mL), low cytotoxicity against NIH/3T3 cells and non-mutagenic effect. On the other hand, 2[5-(4-fluorophenyl)-3-(5-chlorothiophen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(4-bromophenyl)thiazole (4) can be considered as the most promising anticancer agent against A549 cancer cells owing to its notable inhibitory effect on A549 cells with an IC50 value of 62.5 mu g/mL when compared with cisplatin (IC50 = 45.88 mu g/mL) and low cytotoxicity against NIH/3T3 cells. (C) 2014 Elsevier Masson SAS. All rights reserved.