The presence of Streptococcus pneumoniae in chronic otitis media was determined with a new antigen detection kit, the NOW test. The NOW test was originally designed as a urinary antigen test but was adapted to middle-ear effusions for the present study. Middle-ear effusions from 52 children were studied. Streptococcus pneumoniae was cultured from 10 per cent of the effusions. The NOW test was positive in 23 per cent of the effusions, 80 per cent of culture positive and 17 per cent of culture negative effusions. The NOW test proved to be rapid, simple, reliable and relatively inexpensive for the detection of pneumococcal antigen in the middle-ear effusions. This test may prove valuable for the management of children with acute otitis media who undergo tympanocentesis.