Data derived from morphometric, allozymes and RAPD analyses were compared, in order to investigate the possible relationships between morphologic and genetic variation observed in seven Mediterranean red muller (Mullus barbatus) populations. An absence of correlation between morphological and genetical variability patterns was found, at least for the part of the genome screened by allozymes and RAPD markers. However, heterozygotes for four allozyme loci showed a tendency towards lower morphological variance than homozygotes