The HeI photoelectron spectrum (PES) of the (CH3CH2CH2)(2)N radical is obtained by pyrolysis of di-propylnitrosamine (CH3CH2CH2)(2)NNO at 615 +/- 0.5 degrees C. Except for obvious PES bands of the NO species, at least four new PES bands emerge in the PE spectrum of the pyrolysis products of the (CH3CH2CH2)(2)NNO compound. In order to assign the PES bands of (CH3CH2CH2)(2)N, an improved density functional theory calculation has been carried out. A sharp peak with the lowest ionization energy at 8.36 +/- 0.02 eV comes from electron ionization of the HOMO(4b(1)) of the (CH3CH2CH2)(2)N radical, corresponding to the ionization of (CH3CH2CH2)(2)N((XB1)-B-2) to (CH3CH2CH2)(2)N+(X(1)A(1)).