Ghrelin and obestatin, two antagonist peptide hormones, are purportedly involved in stimulating appetite and controlling energy balance in humans. Serum ghrelin level is also associated with iron deficiency anemia (IDA), but no study has yet been made of the obestatin level in patients with IDA, even though both hormones are a single gene product. Therefore, the purpose of this investigation is to see whether there is a link between IDA and these two hormones among other hematological parameters in patients with IDA. To measure ghrelin and obestatin, human saliva and serum were collected from 30 women with IDA, aged 31.7 ± 10.7 years, and 30 control women, aged 30.2 ± 8.0 years, with repeated collection of samples over a period of 1 week and 1 month. Saliva and serum ghrelin levels were measured by ELISA. Serum hemoglobin, ferritin, hematocrit and total iron-binding capacity (TIBC) values were determined with an Olympus AU2700. Saliva and serum ghrelin and obestatin levels were significantly lower in the IDA group compared with controls; these levels increased slightly above baseline with iron treatment, but remained below the control values. Furthermore, and as expected, serum hemoglobin, ferritin, and hematocrit levels were significantly increased with iron treatment, while total iron-binding capacity decreased compared to baseline concentrations. The findings suggest that IDA might be linked to imbalance of circulating (serum) and non-circulating (saliva) ghrelin and obestatin levels. Decreased ghrelin and obestatin might destroy iron homeostasis through its effect on intestinal absorption. Measuring these hormone levels might be useful for monitoring the response to iron treatment. Also, serum and saliva levels for both hormones were well correlated. Thus, using saliva in place of serum for monitoring the two hormones should minimize inconvenience and patient discomfort.