Abstract. Gap equations at finite temperature are deduced in the pure isoscalar pairing case ($T=0$). Expressions of the nuclear statistical quantities, i.e. the energy, the entropy and the heat capacity are deduced. A numerical study is then performed using the schematic one-level model.
It is found that the behavior of the isoscalar neutron-proton gap parameter $\Delta^{T}_{np} = 0$ as a function of the temperature is similar to that of $\Delta_{pp}$ and $\Delta_{nn}$ in the conventional Finite Temperature BCS (FTBCS) approach. The presence of a critical temperature value beyond which $\Delta^{T}_{np} = 0$ is null is noted.
Dealing with the nuclear statistical quantities, their behavior as a function of the temperature is similar to that obtained using the conventional FTBCS theory in the pairing between like-particles case. An increase in the energy value is noted compared with other types of pairing.

Key words: Pure isoscalar neutron-proton pairing, Temperature, Statistical quantities.