Abstract. This paper presents results of experimental efforts pointed towards morphology improvement of HgCdTe layers grown by MOCVD on GaAs substrates. Selected growth parameters on morphology state are presented. The substrate issues like its quality and crystallographic orientation have been discussed. Also influence of HgCdTe layer thickness on its surface roughness is described.It is shown that extensive characterization studies using accessible equipments and methods: atomic force microscopy (AFM), secondary electron microscopy (SEM), laser scatterometer and Nomarski microscopy, have provided invaluable information about the correlation between defect formation and the influence of specific growth parameters.