The contamination of poultry in the Netherlands withSalmonella entcritidiswas tested. For this, different methods(detection ofS. enteritidisin faecal samples of 25 g; detection ofS. enteritidisin cloacal swabs; detection ofS. enteritidisby serological testing of antibodies in serum)were compared for their efficiency to detectS. enteritidisin flocks of poultry. Testing of faecal samples clearly yielded the best results. This method was used in a transmission study, in which 14 flocks descending from a contaminated primary mother flock were screened for the presence ofS. enteritidis.The method was also used for screening 49 flocks of laying hens and 52 flocks of broiler chickens throughout the Netherlands. From the transmission study it became clear thatS. enteritidis,phage type 2(Dutch phage set)was isolated both from the mother flock and from five of the descendent flocks. Screening of poultry flocks for the presence of salmonella revealed that salmonella was present in 47% of the layer flocks and in 94% of the broiler flocks.S. enteritidiswas isolated from 15% of the flocks screened.