AbstractAntinuclear antibody (ANA) immunofluorescence tests, using HEp‐2 cells, were performed on 100 children without a history of connective tissue disease. Eighteen (18%) were positive at titres<1:40, nine (9%) being greater than 1:160. Interlaboratory variability was demonstrated with some specimens. No association with possible intercurrent infection was found to account for positive results. Of 44 children with proven infections five (11%) were positive. Antinuclear antibody may be found in some normal children when using the sensitive HEp‐2 cell substrate, and in the absence of clinical features should not necessarily suggest the presence of a connective tissue dise