Osteoporosis and osteopenia are an important endocrine-metabolic disease that affect women and men from a certain age and it has a high risk and health cost. The aim of this short communication is to show that fasting calcium/creatinine ratio in patients with calcium stones is a marker of bone resorption.We studied 180 patients with renal stones with calcium composition and the relationship of them between the calcium/creatinine in urine after 8 h of fasting with bone densitometry (T-score) and values of bone resorption marker β-crosslaps (ng/ml). The Pearson correlation test was applied for the analysis of linear correlations between quantitative variables.We have observed a statistically significant positive linear correlation between the fasting calcium/creatinine and serum and β-crosslaps (R = 0.534, p < 0.0001) and a statistically significant negative linear correlation between fasting calcium/creatinine and T-score of bone densitometry in hip (R = -0.237, p = 0.002), femoral neck (R = -0.217, p = 0.009) and lumbar spine (R = 0.292, p = 0.001).The fasting ratio calcium/creatinine in urine is associated with increased levels of β-crosslaps marker and therefore may be useful as a marker of bone resorption in these patients.