Properties of selective-area-grown (SAG) ternary and quaternary layers of InGaAs and InGaAsP produced by metal organic vapor phase epitaxy (MOVPE) have been investigated by using a combination of micro-photoluminescence and synchrotron-based micro-beam X-ray fluorescence techniques. Significant variations of the group-III element composition with increase of the oxide mask width and with decrease of the gap between the masks were observed in both ternary and quaternary layers. In contrast, concentration of the group-V elements in quaternary layers does not show any significant change. Effects of the SAG growth on variations of the group-III element composition become more pronounced with increase of the growth pressure. (C) 2003 Elsevier Science B.V. All rights reserved.