Nephrolithiasis, a common condition in our community, is characterised by its high recurrence rate and risk of long-term complications. Identifying underlying metabolic abnormalities is crucial for effectively preventing and treating this disease. This study aimed to classify metabolic alterations associated with the formation of kidney stones in patients evaluated over two decades. Data from patients undergoing the Metabolic Study of Renal Lithiasis according to Charles C. Pak protocol were examined. The results revealed that only 3% of patients lacked detectable metabolic abnormalities. In the remainder, several causes were identified, with hypercalciuria being the most hipercalciucommon, followed by hypocitraturia, hyperuricosuria, hypomagnesuria, and other less frequent causes such as gouty diathesis or renal tubular acidosis. Within hypercalciuria, absorptive hypercalciuria type II stood out as the main cause, followed by renal origin and other less common subtypes. Hypercalciuria was also frequently associated with hypocitraturia and hyperuricosuria. These findings reflect the prevalence of metabolic abnormalities related to excess calcium in the urine, with absorptive hypercalciuria type II being the most relevant. Timely diagnosis, through comprehensive metabolic studies, allows for implementing dietary measures and specific therapies to prevent recurrences and protect renal tissue.