Aim: Evaluation of serum ferritin and vitamin D levels in females with chronic telogen effluvium (TE) or female pattern hair loss (FPHL), in order to validate their role in these common hair loss diseases. Methods: Eighty females (18 to 45 years old) with hair loss, in the form of TE or FPHL, and 40 age-matched females with no hair loss were included in the study. Diagnosis was based upon clinical examination as well as trichogram and dermoscopy. Serum ferritin and vitamin D<sub>2</sub> levels were determined for each participant. Results: Serum ferritin levels in the TE (14.7 ± 22.1 μg/l) and FPHL (23.9 ± 38.5 μg/l) candidates were significantly lower than in controls (43.5 ± 20.4 μg/l). Serum vitamin D<sub>2</sub> levels in females with TE (28.8 ± 10.5 nmol/l) and FPHL (29.1 ± 8.5 nmol/l) were significantly lower than in controls (118.2 ± 68.1 nmol/l; p < 0.001). These levels decreased with increased disease severity. Serum ferritin cut-off values for TE and FPHL were 27.5 and 29.4 μg/l, respectively, and those for vitamin D were 40.9 and 67.9 nmol/l. Conclusion: Low serum ferritin and vitamin D<sub>2</sub> are associated with hair loss in females with TE and FPHL. Screening to establish these levels in cases of hair loss and supplementing with them when they are deficient may be beneficial in the treatment of disease.