We performed studies of the ac-susceptibility and thermal expansion of polycrystalline Ce2Fe16.65MnO0.35 and Ce2Fe16Mn1 compounds under high hydrostatic pressure up to 10 kbar in the temperature range 10-300 K. The application of pressure leads to a suppression of both the ferromagnetic state (d Theta (T)/dp = - 30 K/kbar) and the large positive spontaneous volume magnetostriction for Ce2Fe16.65Mn0.35 Compound. The effect of pressure on Neel temperature is moderate (d/T(N)dp = - 2.3 K/kbar for Ce2Fe16Mn1). Re-entering increase of ac-susceptibility was observed at pressures higher than I kbar below 80 K for Ce2Fe16Mn1. The results show not only a strong correlation between magnetic properties and the lattice volume but also the significant role of the Mn content.