Molecular weights and band counts of sarcoplasmic proteins in four populations of Salmo trutta macrostigma living in Mediterranean region of Turkey were analyzed with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) method and densitometric analysis. 13, 17, 14 and 15 sarcoplasmic protein bands were obtained, respectively from Esen Stream (I), Aksu Stream (II), Alara Stream (III) and Alakir Stream (IV) populations. Protein bands with molecular weights 210, 93 and 30 kDa were found solely in population II. 116 kDa bands were present in all populations but population I with density of bands with molecular weights over 97 kDa was smaller than all the other populations. Densitometric analysis of population IV showed that it differs from the three other poulations by having all protein bands except for 45 kDa band which were at low densities.