The concentrations of calcium, phosphorous, magnesium, iron, glucose, cholesterol, total lipids (mg/100 ml blood) and total proteins, albumin and globulin (g/100 ml blood) were estimated in the serum of 26 mature non-pregnant female one-humped camels (Camelus dromedarius) during the different phases of ovarian activity. A significant (P/ 0.05) increase of both calcium and phosphorous levels was observed in the serum of she-camels having mature follicles in their ovaries than those having smooth ovaries. Serum magnesium levels showed higher values among she-camels with mature follicles or corpora lutea than those with no structures in their ovaries. However, this increase was significant (P/ 0.05) only during the mature folliclar stage. More over, a significant (P/ 0.001) increase of serum cholesterol level was observed during non-follicular stage, when compared with the other two stages of ovarian activity.