The reaction of 1,3,5-triethyl-1,3,5-triazinane (1b) and 1,3,5-trimethyl-1,3,5-triazinane (1c) with sodium hydrogen sulfide has been studied. The products were the corresponding thiadiazinanes 2 and dithiazinanes 3. The rates of the reaction, together with that of 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazinane (1a), were studied by H-1 NMR spectroscopy. Their relative rates of reaction with HS- were as follows: 1c, 1; 1b, 19; 1a, 31. The rates of hydrolysis were studied for the same three compounds. In this reaction, the relative rates were as follows: 1c, 1; 1b, 12; 1a, 24. The reactions of 1,3,5-trioxane (4a) and 2,4,6-trimethyl-1,3,5-trioxane were also studied. These two compounds did not react with HS- or were hydrolyzed under the conditions used for the reactions of 1a-c.