Gas chromatographic and mass spectrometric properties of cyclic methyl and n-butyl boronates of 13 beta blockers and bronchodilators were investigated for potential use in screening and quantitation in biological materials of interest. The tested compounds included acebutolol, atenolol, labetalol, levobunolol, metoprolol, nadolol, oxprenolol, pindolol, propranolol, sotalol, albuterol, and isoproterenol. The cyclic methyl boronates were superior in gas chromatographic properties to the corresponding n-butylboronates of these compounds. Higher weights of fragments obtained with n-butyl boronation may be advantageous for analyses of comRlex biological matrices. Mass spectra and retention times relative to SKF-525A are provided.