The analysis of the steady-state and transient photoluminescence (PL) of PbS quantum dots (QDs) of diameter in the 3.2鈥?.9 nm range in porous matrixes at temperatures 77鈥?00 K shows that QDs of different sizes possess entirely different temperature dependencies of their PL properties. The data indicates the presence of two emissive 鈥渋n-gap鈥?states in the low-energy electronic structure of the QDs with characteristic dependencies on QD size and temperature. The lowest energy state is associated with surface defect states while the higher energy state is 鈥渋ntrinsic鈥?and arises due to size-dependent splitting of the lowest excitons.