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The study of the season effect on the plasma thyroxin (T-4) and triiodothyronin (T-3) concentrations in camel was performed on 5 castrated male camels, 6 to 8 years old. The herd was bred according to the nomadic system in Guelmim (desert area in the southern Morocco) where the ambient temperature ranged from 6 to 20degreesC during the humid season (November - April) and from 19 to 40degreesC during the dry season (May - October). Blood samples were collected every 45 days over the year at early morning before going to the pasture. The mean body temperature varied from 36.7 +/- 0.2 to 37.1 +/- 0.2degreesC in the morning and from 38.0 +/- 0.2 and 38.7 +/- 0.2degreesC in the evening. The mean plasma T-3 and T-4 concentration ranged from 78.0 +/- 2.7 ng/100 ml to 94.0 +/- 5.4 ng/100 ml and from 10.3 +/- 0.18 mug/100 ml to 11.3 +/- 0.26 mug/100 ml, respectively. There was a significant correlation between the plasma T-3 and T-4 concentrations (r = 0.82; p < 0.01). The season has a significant effect (p < 0.05) on the plasma T-3 and T-4 concentrations with high levels during winter and low levels during summer. Negative correlation was observed between the temperature gap and the plasma T-3 (r = -0.34; p < 0.05) and T-4 (r = -0.42; p < 0.05). This effect is related to a combined effect of seasonal variation of the feed supply, the ambient temperature and photoperiod; however, the part of each factor could not be established.