Pottery was adopted by hunter-gatherers in the Eastern Baltic at the end of the 6th millennium cal BC. To examine the motivations for this cultural and technological shift, here we report the organic residue analysis of ceramic vessels from the earliest pottery horizon (Narva) in this region. A combined approach using GC-MS, GC-C-IRMS and bulk IRMS of residues absorbed into the ceramic and charred surface deposits was employed. The results show that despite variable preservation, Narva ceramic vessels were preferentially used for processing aquatic products. We argue that pottery was part of a new Late Mesolithic subsistence strategy which included more intensive exploitation of aquatic foods and may have had important implications, such as increased sedentism and population growth.