Objective: To evaluate the in vitro antischistosomal activity of two new synthetic benzimidazole-related compounds: NBTP-OH and NBTP-F. Methods: Schistosoma adult worms were recovered from mice infected with Schistosoma mansoni cercaria, washed and then incubated in the culture media with different concentrations of compounds NBTP-OH and NBTP-F up to 72 h. Scanning electron microscopy was conducted to report morphological changes. Results: Incubation of adult Schistosoma mansoni with 10 µg/mL of NBTP-OH for 48 h killed 81.25% of worms. The calculated LC50 and LC90 72 h post-incubation were 6.8 µg/mL and 9.8 µg/ mL, respectively. Exposure of worms to 10 µg/mL of NBTP-F killed 89.5% of worms after 48 h, mostly males (83.3%), the LC50 and LC90 after 72 h of incubation were 4.8 µg/mL and 6.9 µg/mL, respectively. Worms incubated for 72 h with these compounds revealed swelling and deformity of oral sucker, disorganization and erosion of the tegument when examined with scanning electron microscopy. Conclusions: NBTP-OH and NBTP-F possess in vitro antischistosomal activities; however, in vivo studies should be conducted to examine their antischistosomal effects.