We have measured emissions of CH3Cl, CH3Br, and (CH3)2S (DMS) from Holstein cows. In one experiment, two cows were studied in separate metabolic research chambers for a 24-hour period while on a normal diet and were studied for an additional 24-hour period 1 week later after being placed on a diet enhanced in chloride and bromide. Methyl chloride emissions ranged between 0.4¿10-3 and 1.5¿10-3gcow-1d-1, while methyl bromide emissions were much smaller, 3¿10-6-2¿10-5gcow-1d-1. Daily emissions of methane from these cows were 134--180gcow-1d-1, quite similar to values found in many previous studies. A second 24-hour study of two different cows on normal diets yielded daily emissions of 0.6¿10-3 and 0.9¿10-3g CH3Cl, 0--1.0¿10-6g CH3Br, and 191 and 176 g CH4. If these emissions of CH3Cl and CH3Br are representative of the 1.3 billion head of cattle worldwide, then the global source of atmospheric CH3Cl and CH3Br from cattle would be 0.23--0.70 Ggyr-1 and (1--10)¿10-3Ggyr-1, respectively. These emissions of CH3Cl and CH3Br represent <0.02% and <0.005%, respectively, of the total annual global atmospheric sources of these compounds; therefore, emissions of CH3Cl and CH3Br from cattle are insignificant contributors to their total sources. Discovered serendipitously, DMS emissions were between 0.17 and 0.24gcow-1d-1, and chloroform emissions were 2¿10-4-3¿10-3gcow-1d-1. DMS from cattle is not a major source over hemispheric or global scales but could be important in certain geographical regions. Chloroform (CHCl3) emissions were similarly detected and quantified, as were those of C2H5X (X=Cl or Br). ¿ 1999 American Geophysical Union