The synthesis of several new ethyl 2-substituted-aminothiazole-4-carboxylate analogs is described. The prepared compounds were tested for their in vitro antitumor activity against 60 human tumor cell lines by the National Cancer Institute (NCI) and showed potential anticancer activity. Ethyl 2-[3-(diethylamino)-propanamido]-thiazole-4-carboxylate (14) exhibited remarkable activity against RPMI-8226 leukemia cell line with GI50 value of 0.08 microM, and a broad spectrum activity against all the tumor cell lines used with GI50 (MG-MID) value of 38.3 microM. The detailed synthesis and antitumor screening data are reported.