4-Carbethoxymethyl-2-[(alpha-chloropropionyl/alpha-bromobutyryl/alpha-chloro-(alpha-phenyl) acetyl) amino] thiazoles (2a-c) were synthesized by the reaction of 4-carbethoxymethyl-2-aminothiazole (1) with alpha-chloropropionyl chloride, alpha-bromobutyryl bromide and a-chloro-a-phenylacetyl chloride, respectively, which were then refluxed with ammonium thiocyanate to obtain 5-substituted 2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones (3a-c). 3a-c were stirred with formaldehyde and various secondary amines to gain 15 novel compounds with the structure 5-substituted 5-(N,N-disubstituted aminomethyl)-2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones (4a-o). The antibacterial activities of the compounds against S. aureus ATCC 6538, S. epidermidis ATCC 12228, E. coli ATCC 8739, K. pneumoniae ATCC 4352, P. aeruginosa ATCC 1539, S. typhi, Sh. flexneri and Pr. mirabilis ATCC 14153 were tested using disk diffusion, while the antifungal activities of the compounds against M. gypseum NCPF-580, M. canis, T. mentagrophytes, T. rubrum and C. albicans ATCC 10231 were tested using microdilution.