This paper presents a part of the research results in a section of river Sava that flows through Croatia. The research is conducted in the period from 2003 to 2012. A comparison of condition factors of 20 fish species from 8 different locations of the river Sava has been done. Condition factor was measured by Fulton’s condition coefficient which shows a general state of fishes, as well as the changes which occur depending on the location and physiological cycles in the life of fishes. The average condition factor (CF) was calculated for each studied species on the basis of the measured morphometric parameters. Those average condition factors were compared mutually and with an average condition factor of the river Sava. Condition factors for all fish species range from 0,43 to 2,06. CF higher than 1, at all observed locations, has been recorded for Percidae (max. 1,22), Prussian carp (max. 1,86), Ruffe (1,46) as well as Silver bream (2,06) and Pumpkinseed (1,89) which have the highest CF. The lowest CF was recorder for Loach and Balcan loach at all observed locations (ranging from 0,43 to 0,62 at altogether 6 locations). Average percentages of condition factors of fishes from 8 locations on the river Sava were determined, taking into consideration at least four species and more than ten specimens, which were compared with the average factors for the river Sava and the Republic of Croatia. Average percentages of condition factor in the observed locations of the river Sava, for all fish species, range from the lowest 89.24% at Gornji Varoš to the highest 105.24% at Puska. Condition factors of fishes from river Sava with an average of 98.49% are generally higher than those for inland waters throughout the Croatian with an average of 94.46%. It is necessary to conduct a further research with a larger number of specimens of each species in order to confirm these results.