Objective- To determine the prevalence of nutritional secondary hyperparathyroidism (NSH) in companion and stray cats of Ahvaz. Design- Clinical study. Animals- 80 cats (companion=40 and stray=40) Procedures- This survey was accomplished during a two-year period and based on clinical, radiographic and laboratory findings between 2005 and 2007. The studied cats were divided into two general group (companion and stray) and based on age into groups ≤ 3 months and 3- 6 months. Status of nutrition was studied from using of milk and other dairy products (as a source of calcium). In our survey nutritional secondary hyperparathyroidism was diagnosed in seven cases. The measured biochemical parameters included calcium, phosphorus and alkaline phosphatase (ALP). Results- The most radiographic findings were thin cortex, pathological fractures, constipation, decreased bone density and pelvic and column vertebral deformity. Level of ALP was high in some affected and healthy cats, but difference was not significant (P> 0.05). Calcium and phosphorus were in normal range both groups. Also, on statistical analysis (ANOVA), there was no significant differences between different sexes and companion and stray cats (P>0.05). Nevertheless, prevalence was significantly higher in some companion cats that were fed with high phosphorus and low calcium, as well as in cat's ≤ 3 months (P< 0.05). Conclusion and Clinical Relevance- Nutritional secondary hyperparathyroidism is common partly in Iran, where many cats are fed mainly meat diets. This study showed importance of balanced nutrition special calcium and phosphorus in cats ≤ 3 months.