A non-linear AIDS model was used to estimate substitution patterns across seafood categories at the US retail market level. Results indicate that demand for catfish, crawfish, clams, and salmon products is elastic, suggesting that consumers are sensitive to price changes. In contrast, demand for shrimp and tilapia, mostly imported products, is price inelastic. US consumers would “tolerate” an increase in tilapia price compared to other seafood categories, especially catfish. Tilapia and salmon are found to have the most negative effects on purchases of other seafood products. Catfish is a strong substitute for tilapia; while tilapia is not a strong one for catfish. Promotions play significant roles in seafood purchases, especially among import-dominant products like shrimp, tilapia, and salmon. Future research should first be conducted at the metropolitan level, highlighting market specificity implied by consumers’ demographics; secondly, it should be done at disaggregated levels for each seafood category, product form, and product size.