We reviewed tetracycline and erythromycin disk diffusion susceptibility of 457 isolates of Branhamella catarrhalis. Four isolates were resistant to tetracycline, with MICs for two available isolates of 16 micrograms/ml. Sixteen isolates were in the moderately susceptible range for erythromycin, with an MIC for one available isolate being greater than 8 micrograms/ml. These are the first tetracycline- and (by MIC) erythromycin-resistant B. catarrhalis isolates reported from the United States.