New 4-naphthyl-2-aminothiazole derivatives were synthesized. The newly synthesized compounds were screened for their in vitro antimicrobial and anticancer activities. The results indicated that compound 5b namely 2-(4-methylpiperidine-1-yl)-4-(naphthalene-2-yl) thiazole exhibited highest MIC value (62.5 mu g/ml) against P. aeruginosa in the tested microorganisms. This compound showed equipotent antifungal effect on C. albicans and C. glabrata as compared with ketoconazole. Compounds 4c, 4d, 5a and 5f showed remarkably antifungal activity against C. albicans. In addition, anticancer activity and cytotoxicity studies were also carried out in Hep-G2 and A549 cell lines to examine the ability of inhibiting the cell growth for 4a-4f and 5a-5f compounds. The cell viability and anticancer activity were determined by MTT assay. 4a-4f compounds has led to an increase in cell proliferation in both cell lines (Hep-G2 and A549 cells), unlike 5a-5f series showed a weak anticancer activity.