Background: Urolithiasis is truly one of the most painful medical condition afflict human being, there are many types of renal stones, one of the most important factors on which urolithiasis treatment depend on is the chemical composition of the stone, prediction of renal stone composition before treatment will help the urologist to choose the suitable line for treatment. Non-enhanced CT offer important information about existence, size, location and predict the chemical composition of the renal stone. Aim: correlation between renal stone composition and Hounsfield Unit and Hounsfield density in non-enhanced CT. Patients and methods: This prospective study was conducted during the period from August 2014 to September 2015 on 50 patients, referred from the Urology department, each has single renal stone of more than 10mm in diameter detected by ultrasound, unenhanced CT scan and KUB were done for all patients, after treatment the stone specimens collected and send for chemical analysis, the chemical composition of each stone was compared with its HU and HD and statistically evaluated. Results: The 50 renal stones were classified in to six groups according to the laboratory results: 14 pure Calcium Oxalate (CO), 10 pure uric acid (UA), 12 struvite (STR), 7 Calcium Oxalate + Hydroxyapatite (CO+HXA), 3 Calcium Oxalate + Hydroxyapatite + Struvite (CO+HXA+STR), and 4 Calcium Oxalate + Uric acid(CO+UA) stones, calcium containing stones were about 56% in the studied samples, a significant relationship (P. value < 0.001) was found between the types of the renal stone and their HU, mixed CO + HXA stones were the highest value (1280 – 1464),then pure CO ( 1080 - 1260), then mixed CO + HXA+ STR (830-980), then the Pure STR stones which show an overlap between their HU (533 – 734) and mixed CO + UA stones HU ( 396 – 586), finally the pure UA stones which are the least HU stones in our study (215 – 342),HD value was obtained from dividing the HU by stone diameter, the result was ranging from 18 – 69.4, various types of stones show significant relationship with their HD (P value < 0.001), the pure CO stones show the highest HD (59.5) while the pure uric acid stones show the lowest HD (20.5), still there was overlap between STR and mixed CO + UA stones where they show HD of 23.2-32 AND 23. 3-25. 6 respectively. Conclusion: Non-enhanced CT can determine the chemical composition of most renal stone types by measuring the HU and HD of the stone.