The potential of chemically treated common reed (Phragmites australis) hay in maintenance diets for sheep. 2. A comparison between NaOH treatment and ammoniation with or without molasses with respect to digestibility, intake and nitrogen retention. A digestibility experiment was conducted with sheep to determine the effect of NaOH treatment and ammoniation in combination with three levels of molasses. Intake, digestibility and N utilization were evaluated in a design consisting of three 3 x 3 Latin squares. Both chemical treatments improved organic matter intake and the digestibility of neutral detergent fibre (NDF) and organic matter highly significantly while molasses had a negative effect on these parameters in the case of both chemically treated diets. Chemical treatment had no significant effect on apparent N digestibility in the absence of molasses. In the case of ammoniation, however, 3 and 8% molasses decreased apparent N digestibility by respectively 12,6 and 22,8% compared to the untreated diet. In agreement with this observation, metabolic faecal N as a percentage of organic matter intake was increased by 36,4 and 48,4% respectively. Both chemical treatments decreased urine N as a percentage of N intake at the 0 and 3% molasses levels, while molasses per se significantly decreased the percentage of urine N in the case of the untreated diet. N retention was significantly improved by both chemical treatments, but the effect of molasses was not consistent between treatments.