The aim of the research is to estimate the potential demand for certified clams in Italy and to investigate the determinants of maximum amount that respondents are willing to pay for this product. Quantitative analysis was used based on 1,067 face-to-face interviews collected in 3 Italian regions in the north bordering the Adriatic Sea (Friuli-Venezia Giulia, Veneto, and Emilia-Romagna) carried out during 2008. The consumers' willingness to pay (WTP) is measured using a contingent valuation method. In order to estimate separately the determinants of the probability that respondents are willing to pay and the maximum that they are willing to pay, a generalization of Tobit model was adopted. The results indicate that consumers are willing to pay a premium price mainly to purchase better quality products. The research provides some initial insight into consumers' WTP that can be useful for certified fish farming.