The isobaric specific heat capacity c(p) of gaseous pentafluoroethane was measured and the behavior was presented. With a flow calorimeter, 29 c(p) data of pentafluoroethane were measured at temperatures T from (303 to 343) K and at pressures p from (0.5 to 2.4) MPa. Some of them were measured in the immediate vicinity of the saturation curve. The expanded uncertainties (k = 2) of the temperature measurements U(T) and the pressure measurements U(p) are estimated to be below 50 mK and 11 kPa, respectively. That for c(p) measurements U-c(c(p)) is assessed to extend from (14 to 60) J.kg(-1).K-1. Then, the c(p) measurements including the previous 12 measurements were compared with some available equations of state. Using these confirmed data, the c(p) behaviors of gaseous pentafluoroethane were presented in a c(p)-p diagram.