Rationale Seafood is a major allergen in adults with food hypersensitivity in Japan. Recently seafood anaphylaxis is increasing in children. We measured serum specific IgE to salmon roe, Alaska Pollack roe, clam, oyster and scallop in children with seafood allergy to investigate sensitization to these allergens. Methods Forty-five patients, the average age 3.6 years, with seafood allergy are enrolled in the study. Those consist of 28 fish allergy, 26 shellfish allergy, 13 mollusks allergy and 5 fish roe allergy. Specific IgE antibodies to salmon roe, Alaska Pollack roe, clam, oyster and scallop were measured by UniCAP specific IgE kit. Results Forty-one patients with fish and/or shellfish allergy were divided into 3 groups; group1 (15 cases): fish only, group2 (13 cases): fish+shellfish, group3 (13 cases): shellfish only. Positive IgE to one or more mollusks were identified 85% in group 3, 56% in group 2 and 27% in group 1. One third of the 3 groups were positive IgE to one or both fish roe. Twelve patients had history of hypersensitivity to mollusks and 8 of these were positive IgE to all 3 mollusks tested. Three patients with anaphylaxis to salmon or Alaska Pollack roe had positive IgE (Score 3 ∼4) to both fish roes. Conclusions The results suggest that measurements of serum specific IgE to these seafood allergens are useful for diagnosis of fish roe and mollusks in patients with fish or shellfish allergy.