Nitrous oxide (N2O) was measured during the first German SOLAS (Surface Ocean -- Lower Atmosphere Study) cruise in the tropical North Atlantic Ocean on board R/V Meteor during October/November 2002. About 900 atmospheric and dissolved N2O measurements were performed with a semi-continuous GC-ECD system equipped with a seawater-gas equilibrator. Surface waters along the main transect at 10¿N showed no distinct longitudinal gradient. Instead, N2O saturations were highly variable ranging from 97% to 118% (in the Guinea Dome Area, 11¿N, 24¿W). When approaching the continental shelf of West Africa, N2O surface saturations went up to 113%. N2O saturations in the region of the equatorial upwelling (at 0--1.5¿N, 23.5--26¿W) were correlated with decreasing sea surface temperatures and showed saturations up to 109%. The overall mean N2O saturation was 104 ¿ 4% indicating that the tropical North Atlantic Ocean is a net source of atmospheric N2O.