The physicochemical changes in sardine flesh during frozen storage at −18C were studied in terms of salt-soluble protein extractability, nonprotein nitrogen (NPN), pH, myosin and actin denaturation enthalpies, color, fatty acid methyl esters and proteolytic activity in surimi wastewaters. Furthermore, the functional properties of the produced kamaboko gels were studied based on two experimental factors: (1) frozen storage time (five levels) and (2) various additives (three levels). The NPN and pH changes showed a similar trend (P < 0.05) throughout the storage. Myosin transition enthalpy significantly decreased throughout the storage and strongly negatively correlated with storage time (r = −0.987). Color deterioration was evidenced by the decrease in lightness (L*) and whiteness index (WI) as well as the increase in greenness (−a*) and yellowness (+b*) of sardine mince (P < 0.05). Protease activity in surimi wastewaters increased on day 20, due to either sample variation or better extraction, and showed a downward trend thereafter. A gradual increase was noticed in gel hardness and cohesiveness after 10 days of storage due to protein aggregation. Hardness and cohesiveness, as well as L* and WI, were positively affected by the addition of CaCl2 and microbial transglutaminase (MTGase), while springiness was only affected by MTGase addition. Overall instrumental evaluation showed that kamaboko gels of acceptable quality could be produced from sardines frozen stored up to 20 days.