To evaluate the adaptation of electrodermal techniques for cystic fibrosis screening, skin surface bioelectric measurements were recorded from 37 established cystic fibrosis patients, 45 asthmatic patients, and 10 normal controls, ranging in age from 6 to 22 yr. Six skin potential and six skin conductance measures of sweat gland activity without the collection of sweat distinguished between the cystic fibrosis, normal, and asthmatic groups (F ratios>10.0; p<0.0001). Discriminant analysis using the two best electrodermal measures (the mean of five preresponse potential levels and the mean of five preresponse conductance levels for each subject) to assign experimental group membership matched actual group membership with 92.7% accuracy. We believe these results warrant further investigation of electrodermal procedures as a direct, simple, yet noninvasive means of screening for cystic fibrosis.