The effect of modified atmosphere packaging (MAP) with and without a moisture adsorbent, on the quality of squid (Sepia officinalis) during chilled storage, was evaluated. Chemical and microbiological tests were carried out to measure the amount of spoilage and the resulting loss of fish freshness during 12 days of storage at 3°C. After 11 days, trimethylamine nitrogen (TMA-N) increased from 0.4 mg/100 g in fresh samples to 24 mg/100 g in MAP with adsorbent and 35 mg/100 g in the other samples. Total volatile basic nitrogen (TVB-N) increased from 18 mg/100 g in fresh samples to 112 mg/100 g in MAP with adsorbent and 158 mg/100 g in control samples. Counts of aerobic psychrotrophic microorganisms and presumptive Pseudomonads were more than 10 times lower in both MAP treatments compared to the control, in which counts exceeded 106 cfu/g on day 9, and 107 cfu/g on day 12.