Either HIV or HCV monoinfection could result in an abnormal status of platelets. As two key indicators reflecting activation and function of platelets, the changes of platelet counts and mean platelet volume (MPV) in HIV/HCV-coinfected patients have not been clearly identified. In the present study, a total of 318 former plasma donors were investigated in 2006, and 66% (201 individuals) of primary recruiters were followed up in 2014. By horizontal comparison in 2006, the decrease of platelet counts in HIV/HCV coinfection was greater than that in HIV or HCV monoinfection. MPV scores were lower in HIV monoinfection compared with healthy controls, while no difference was found in HIV/HCV coinfection. Platelet counts were shown to be negatively correlated with MPV scores in total recruited population (r = 0.432, P < 0.001). Interestingly, by comparison of data from two time points of 2006 and 2014, significant decrease of platelets (P = 0.004) and increase of MPV (P = 0.004) were found only in HCV monoinfected patients, which may associate with slow progression of hepatic fibrosis induced by chronic HCV infection. Nonetheless, no significant changes of platelet counts and MPV were found from 2006 to 2014 in coinfected patients. In conclusion, HCV coinfection aggravated the decrease of platelet counts, but not MPV score in chronic HIV infection. MPV showed poor applicability in reflecting the status of platelets in HIV/HCV-coinfected patients.