In this paper, we have studied numerically thermal performances of a parabolic trough collector (PTC) working with different nanofluids. Simulations are carried out for 5% nanoparticles' volume concentration. The ultrafine particles that have been suspended in the base fluid (Syltherm800) are the aluminum oxide (Al2O3), the copper (Cu), the cupric oxide (CuO) and the silver (Ag). The results show that the convection heat transfer coefficient increased with the suspension of the nanoparticles. The overall heat loss coefficient of the PTC has been found to decrease when using nanofluids. The maximum enhancement in thermal performances of the PTC has been recorded for the silver nanoparticles which reach approximately 36% increase in the convection heat transfer coefficient and 21% decrease in overall heat loss coefficient.