Four ruminally cannulated Holstein cows were used in a 4 × 4 Latin square design to determine the effect of feeding linted, delinted and extruded linted whole cottonseed (WCS) on nutrient digestibility and ruminal fermentation. Result showed that crude protein digestibility was lower in linted and delinted WCS treatments than control and extruded linted WCS treatment. Cows fed extruded delinted WCS had the highest digestibility of neutral detergent fibre compared with those fed the other diets. The inclusion of processing WCS did not alter ruminal pH and ruminal total and molar proportion of volatile fatty acids, however, feeding delinted WCS reduced the ruminal ammonia nitrogen concentration and acetic:propionic acid ratio.