THIS STUDY WAS CARRIED OUT TO EVALUATE THE EFFECT OF HIGH HYDROSTATIC PRESSURE (HHP) TREATMENT ON MICROBIAL BEHAVIOR AND THE SHELF-LIFE EXTENSION OF COHO SALMON AND ABALONE DURING CHILLED STORAGE AT 4 °C. FOR SALMON, HHP TREATMENTS WERE APPLIED AT 135, 170, AND 200 MPA FOR 30 S, WHILE ABALONE TREATMENT CONSISTED OF 500 MPA FOR 8 MIN AND 550 MPA FOR 3 OR 5 MIN. SPOILAGE BACTERIA (PSEUDOMONAS SPP. AND HYDROGEN SULFIDE-PRODUCING BACTERIA, MAINLY SHEWANELLA PUTREFACIENS), AS WELL AS AEROBIC MESOPHILIC AND PSYCROPHILIC MICROORGANISMS, WERE ENUMERATED IMMEDIATELY AFTER TREATMENT AND THROUGHOUT SUBSEQUENT STORAGE AT 4 °C. RESULTS HAVE SHOWN THAT HHP TREATMENT REDUCED THE INITIAL MICROBIAL COUNTS OF SALMON FROM 3.16 TO 2.2 LOG UNITS, MOREOVER ABALONE WAS REDUCED FROM 1.3 LOG TO UNDETECTABLE LEVELS (65 DAYS IRRESPECTIVE OF HHP TREATMENT APPLIED.