PURPOSE: Introduction of complementary food usually leads to decreasing intakes of long-chain n-3 polyunsaturated fatty acids (n-3 LC-PUFA), compared to full breastfeeding. In the randomised controlled PINGU intervention trial, we tested the effects of complementary foods with different contents of alpha-linolenic acid (ALA) and docosahexaenoic acid (DHA) on term infant LC-PUFA status. METHODS: Healthy infants born at term were randomised to receive from the introduction of complementary feeding at the age of 4 to 6 months until age of 10 months ready-made complementary meals either with ALA-rich rapeseed oil (intervention group (IG)-R), with salmon twice weekly to provide preformed DHA (IG-F), or with linoleic acid-rich corn oil (control group, CG). Fatty acid composition was assessed in erythrocyte (RBC) and plasma glycerophospholipids. RESULTS: Complete data of fatty acids in RBC (plasma) were available from 158 (155) infants. After intervention, infants assigned to IG-F showed higher RBC and plasma percentages of eicosapentaenoic acid (EPA), DHA, and total n-3 LC-PUFA than CG (each p < 0.001). In IG-R, levels of ALA and the ratio of ALA to LA in plasma and RBC (all p < 0.0001) as well as RBC-EPA (p < 0.0001) were higher than in CG, while DHA levels did not differ between IG-R and CG. CONCLUSIONS: Regular fish consumption during complementary feeding enhances infant EPA and DHA status. The usage of rapeseed oil in small amounts concordant with EU-law for commercial meals enhances endogenic EPA-synthesis, but does not affect DHA status. Provision of oily fish with complementary feeds is advisable to prevent a decline of DHA status. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov , identifier: NCT01487889, title: Polyunsaturated fatty acids in child nutrition-a German multimodal optimisation study (PINGU).