This study was carried out to find out the relationships of RNA, DNA content, RNA/DNA ratio and protein levels with different size length individuals ofPenaeus indicas. RNA, DNA content, and RNA/DNA ratio were found to be high in small sized prawns, with increased amount of protein. There was a decline in RNA concentration as size of the prawns increased, thus showing an inverse relationship. Though DNA values also showed a slight decline with increase in size, among large sized prawns there was a tendency to conserve DNA content. RNA/DNA ratio has been found useful in correlating growth (in terms of protein increase) only in small sized prawns.