Correction: In the article “Analysis of Single Cyclic Nucleotide-Gated Channels in Olfactory Receptor Cells,” by F. Zufall, S. Firestein, and G. M. Shepherd, which appeared on pages 3573–3580 of the November 1991 issue, traces Ab andBc in Figure 1 are identical, because of an inadvertent error in preparing the figure, and should be disregarded. The other traces in series A and B show correctly that cAMP and cGMP acted on the same channel. The conclusion in the text regarding the figure (page 3574), “that cAMP and cGMP acted on the same channel in our patches,” remains correct. The error has no significance for the overall results of the paper or their interpretation.