Co-2(Nb1-xVx)Sn, Co2NbSn1-yGay. and Co2NbSn1-zAlz alloy systems exhibit itinerant ferromagnetic behaviour as observed from magnetization and susceptibility studies. Spin fluctuation effects are observed from magnetization, resistivity and thermopower data. The thermal expansion data gave evidence of structural transformation effects due to the formation of a pseudogap in the density of states near the Fermi level.