Starting from a cellulose trinitrite solution prepared by dissolving the polymer in a N 2O 4-Me 2NCHO mixture, cellulose sulfation was investigated with different sulfating agents under homogeneous reaction conditions. At room temperature the degree of substitution (ds) increased in the order H 2SO 4 ⪡ H 2NSO 3H ∼ NOSO 4H < SO 2 < ClSO 3H < SO 3 < SO 2Cl 2. Generally, the nitrite group in the 6-position was the preferential reaction site at +20°C. With SO 2Cl 2 the highest ds values are reached, and considerable sulfation in the 2-, and to some extent in the 3-position, was found by 13C NMR spectroscopy after decomposition of the residual nitrite groups. At −20°C the secondary nitrite groups in the 2-position were definitely the preferred reaction site for sulfation of the cellulose trinitrite with SO 3. The results are discussed in relation to stability and availability of the nitrite groups.