A Danish surveillance group established after the introduction of oral vitamin K prophylaxis monitored Danish cases with late onset vitamin K deficiency bleeding by regular questionnaires to all paediatric departments. Six cases were reported, one of whom died and three are severely handicapped. All cases occurred among an estimated 134,500 infants given a single oral 1 mg vitamin K dose at birth. No cases have been reported so far during the existent regimen: 2 mg at birth and 1 mg weekly orally administered vitamin K during the first 3 months of life, given to at least 163,000 infants. The present study is concordant with the only other study on weekly peroral prophylaxis published. We consider the mentioned weekly regimen safe and appropriate.