Carbon doping in InAlAs material grown with LP-MOVPE has been studied. Carbon tetrabromide (CBr4) has been used as a source of carbon. We investigated the influence of the growth parameter on the carbon incorporation. Carbon concentrations as high as 3 x 10(19) cm(-3) were achieved at the low temperature of 530 degreesC and the low V/III ratio of 20. Post-thermal annealing was required to activate carbon atoms. Hole concentrations as high as 1.8 x 10(19) cm(-3) have been obtained.