Senescence modifies renal electrolyte handling, and in some circunstances may promote hypercalciuria. Moreover, it has been documented that reduced light exposure can cause alterations in serum levels of vitamin D and intact parathyroid hormone in the elderly. Objective: Thus, we decided to investigate if differences in light exposure between summer and winnter period induced a significant difference in the renal excretion of calcium, phosphorus in healthy very elderly volunteers. Material & Methods: 50 healthy elderly (older than 75 years) who lived in Buenos Aires (34 degrees south latitude), with calcium intake of 800 mg/day, and sun exposure of more than 2 hours per week were evaluated. In each volunteers was measured calcium, phosphorus, (serum, urinary, and fractional excretion), and 25-hydroxy vitamin D, and intact parathyroid hormone. Statistical analysis was performed by applying Wilcoxon test. Results: Average age: 80 years, No significant seasonal differences between measured parameters was found except for 25-hydroxy vitamin D, and intact parathyroid hormone which were lower and higher, respectively in winter. Conclusion: No significant seasonal differences were documented in urinary calcium, phosphorus indeces in very old peolpe.