This experiment was carried out to evaluate the sanitary quality of commercially frozen sea foods. One hundred and sixteen samples in six different items from several refrigeration plant in Busan city were examined from March to December in 1974. In addition, the changes in bacterial density through the process from thawing, round or semifilleted frozen alaska pollack to the finishing as frozen fillet blocks were observed. To evaluate the sanitary quality, sanitary indicative bacteria such as total coliform, fecal coliform, fecal streptococci and enterococci as well as plate counts were determined. From the results, the median value of fecal coliform MPN was 20 per 100 grams of the samples and that of enterococci was 790. The median value of plate counts was $2.2 imes10^4$ per gram. The plate counts were not correlated with the number of sanitary indicative bacteria. The results suggest that enterococci could be used advantageously in preference to coliform organisms as indicative bacteria for the evaluation of sanitary quality of frozen sea foods. The plate counts at $20^{circ}C$ of the samples were 14 times higher than that at $35^{circ}C$. Geometric mean of total coliform MPN was 310 and that of enterococci was 143. Bacterial density was reduced by fleering. Morethan 50 percent for total coliform MPN and $35^{circ}C$ plate counts, and about 35 percent for enterococci MPN and $20^{circ}C$ plate counts were reduced under the contact freezing unit which was generally operated at $-40^{circ}C$. About fifty-five percent of the samples were negative in fecal coliform test and 10 percent of those were exceeded $1.0 imes10^5$ per gram in $35^{circ}C$ plate counts.