The solubilities of 2,3,3,3-tetrafluoropropylene (R1234yf) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) in 1-h exyl-3-m ethylimi d az o lium bis (trifluo romethylsulfo nyl) imide ([HMIM][Tf2N]) were measured at temperatures from 293 to 353 K and at pressures up to 925 kPa. A comparison of the solubilities of R1234yf, R1234ze(E), and hydrofluorocarbons in [HMIM] [Tf2N] was conducted and showed that the solubilities of R1234yf and R1234ze(E) are comparable to those of hydrofluorocarbons but more sensitive to temperature. The solubilities of R1234yf and R1234ze(E) in [HMIM] [Tf2N] were correlated well with a modified Krichevsky-Kasarnovsky equation and the NRTL equation.