Objectives: This study evaluated the effects of four light-curing units on degree of conversion (DC), color change, and stain retention of 5 different drinks in a nanofilled composite resin (Z350, 3M-ESPE). Methods: Two hundred specimens were randomly polymerized for 20 sec in 4 experimental groups: QTH - 550 mW/cm2 for 20 sec; LAS - laser – 300 mW/cm2 for 20 sec; LED 2 - 2nd-generation LED – 1060 mW/cm2 for 20 sec; and LED 3 - 3rd-generation LED – 650 mW/cm2 for 20 sec. After 24 hrs, the DC (%) was measured by FTIR spectroscopy. Subsequently, 10 specimens of each group were immersed in one of 5 solutions (distilled water, red wine, whiskey, coffee, and cola), 40 min per day, during 40 days. Color of all specimens was measured, before and after exposure, with a colorimeter (CIE L a*b*), and the superficial color changes (ΔE*) were calculated. Afterward, specimens were prepared for spectrophotometric analysis, so that stain retention could be obtained. For statistical analyses, a two-way ANOVA and Tukey tests were performed (p = 0.05). Results: DC: QTH presented the lowest DC, with statistical differences for LAS, LED 2, and LED 3. Stain retention: In general, the whiskey and wine groups showed lower means than the cola and coffee groups. There was no statistical difference for light-curing modes for any staining solutions. On the contrary, for stain retention, whiskey showed the highest ΔE for all light-curing modes. Wine presented statistically lower ΔE than whiskey, with no differences for cola and coffee. Water showed the lowest ΔE, without differences for coffee and cola. When light-curing modes were analyzed, LAS and QTH showed higher alterations than LED 2. LED 3 showed intermediate results, without statistically significant differences from any other group. Conclusion: There was no relation among DC, stain retention, and ΔE.