Small-scale fishery monitoring programs can provide valuable information about ex-vessel prices, which are essential for economic analyses and fisheries management. Ex-vessel prices obtained without adequate statistical support can generate inconsistent data and imprecise estimates that do not comply with quality standards that guarantee their usefulness in decision-making. We propose methodological approach for monitoring of ex-vessel prices across a wide range species and coves. In this study, an ex-vessel prices monitoring design was applied to small-scale fisheries in Chile. Our proposal includes: i) development of a sample frame, ii) adoption of a sampling design and estimators for the mean ex-vessel prices and their variance; and iii) determination of sample sizes. A sample frame of 40 species and 54 coves were selected to be monitored, representing close to 94 % of the small-scale landings. We proposed a stratified two-stage sampling design. Sample sizes of 2–5 days/month per species in each cove are suggested, with minimum limits between 3 and 10 transactions/day, in accordance with price variability. In coves where catch is transferred directly from fisher to consumer (shortened trade chains), higher and more variable prices were verified. In contrast, coves that destined their catch only to processing plants, ex-vessel prices remained relatively constant. The precision in mean ex-vessel price estimate depend largely on the number of days sampled. Data collection system used should be updated periodically, in order to capture the dynamics of the seafood trade at the landing sites and ensure precise and accurate estimates of mean ex-vessel prices. The methodological approach for price monitoring developed in this study can be used to implement or improve other ex-vessel price monitoring designs in small-scale fisheries.