Sixteen adult female pigeons were randomly divided into two groups that were fed either corn or peas. Within each group, four pigeons received a supplement of 2.5 g L-carnitine/l drinking water. After an adaptation period of 7d, all excreta were gathered per bird in a 7d collection period. Coefficients of apparent digestibility of dry matter, organic matter, crude fat, crude fiber and nitrogen-free extract and apparent nitrogen retention were calculated from proximate analyses of feedstuffs and excreta. Blood samples were taken at the end of the trial and plasma samples were analyzed for carnitine and related compounds. Supplementation of L-carnitine did not affect digestibility but it did reduce apparent nitrogen retention in the corn-fed pigeons. Plasma analysis of γ-butyrobetain gave indications for a negative feedback mechanism of high L-carnitine dosage on de novo L-carnitine synthesis.