Synthesis and in vitro anti-Helicobacter pylori activity of N-[5-(5-nitro-2-heteroaryl)-1,3,4-thiadiazol-2-yl]thiomorpholines 5-7(a-c) and some related compounds 8a-c and 9a-c were described. The anti-H. pylori activity of target compounds along with commercially available antibiotics such as metronidazole and amoxicillin was evaluated by comparing the inhibition zone diameters determined by the paper disc diffusion bioassay. From our bioassay results against 20 clinical isolates, it is evident that most compounds still had strong activity at 4 and 2 microg/disc (average of inhibition zone >20 mm) while metronidazole had little activity at these doses. Nitrofuran analog 7b containing thiomorpholine S,S-dioxide moiety was the most potent compound tested.