• We compared a rapid latex agglutination test with cultures of throat specimens to diagnose group A β-hemolytic streptococcal pharyngitis in an office setting. The throat cultures were interpreted by two pediatricians independently and evaluated by a reference laboratory. Five hundred seventy-two children participated in the study. The latex agglutination test had a sensitivity of 89.4% and a specificity of 85.7%. Cultures of throat specimens obtained in the office had a sensitivity of 91.9% and a specificity of 91.7% when interpreted by investigator 1, and a sensitivity of 90.0% and a specificity of 95.1% when interpreted by investigator 2. There was no statistically significant difference between the numbers of false-negative results generated by the two procedures. We conclude that although somewhat less specific, the latex test is as sensitive as cultures of throat specimens in the office setting.