The aim of this experiment was to investigate rumen fermentation and some blood parameters of dromedary camels fed with C3 and C4 forage. Four fistulated dromedary adult camels were fed with diets as a changeover design, 30 days for each period. The diets included alfalfa hay + wheat straw (C3 forage) and atriplex+ suaeda + seidlitzia (C4 forage). At the end of the experiment, rumen and blood parameters, gas production of wheat straw and atriplex as a 2 × 2 factorial experiment were determined. The highest blood glucose and urea nitrogen levels were found for camels fed with C3 forage, 2 hr after feeding (p < 0.05). The maximum NH3-N concentration in the rumen was for diets C3 and C4, 2 and 4 hr after feeding (p < 0.05). The lowest rumen pH was observed for C3 diet at 2 and 4 hr and for C4 diet at 4 and 8 hr after feeding. The activity of rumen carboxymethylcellulase (CMCase) and microcrystalline cellulase (MCCase) enzymes was the highest for C3 and C4 diets, 8 hr after feeding, however, during feeding the enzyme activity in C4 was higher than that of 2 hr (p < 0.05). The rumen volatile fatty acid (VFA) concentrations were significantly higher in camels fed C3 forage in comparison with C4 (p < 0.05). The results showed that the gas production potential was significantly higher in treatments containing atriplex, however, the gas production rate was higher in treatment containing wheat straw (p < 0.05). The results suggested that for camels maintained in closed systems, the replacement of C3 forages instead of C4 could be possible and useful.