We report on magnetic susceptibility measurements on a CePtSn single crystal under hydrostatic pressures up to 0.82 GPa. Application of hydrostatic pressure on CePtSn leaves both the N{e}el temperature T_{N} and the AF1--AF2 transition temperature T_{M} nearly intact. This is rather unexpected because the volume contraction was believed to be the main reason for the transformation from the antiferromagnetic Kondo metal with T_{N}= 7.5 CePtSn to a non-magnetic Kondo semi-metal CeNiSn  G.M. Kalvius  et al., Physica B  {289--290}, 256 (2000). The only pressure effect observed is a 25the pressure of 0.82 GPa. A possible scenario for physics of CePtSn is discussed accounting for the observed pressure effects.

PACS numbers: 61.50.Ks, 74.62.Fj