Photocuring process is strongly influenced by photoinitiator systems and light sources. Objective: The aim of this study was to evaluate the photo-curing potential of LED and halogen lights considering self-etching adhesives and composite resins containing diferent photoinitiator systems. Methods: Adhesives - Adper Prompt, ADP (3M/ESPE); Clearfill SE, CFL (Kuraray); Self Etch Bond, SEB (Vigodent); and composites - Filtek Supreme (shade WE), FSU (3M/ESPE), and Ultraseal XT Plus, UXT (Ultradent) were dissolved in ethanol solvent for the absorption study (360-550nm, n=3) using a UV-Vis spectrometer (Hitachi 2000). Emission spectral readings (n=5) of a quartz-tungsten-halogen unit (Optilux 401, Demetron) and a High-powered LED unit (Ultrablue IS, DMC) was obtained between 360-550nm with integrating sphere (LabSphere). The convolution of absorption and emission at each wavelength resulted on the relative curing potential (CP_360-550nm). ANOVA and Tukey test were used for statistical analysis at a pre-defined alpha (0.05). Results: The integrated absorption for both CFL and SEB was similar (p=0.073), but lower than ADP (p<0.001). FSU absorption was remarkably higher than UXT (p<0.001) The maximum absorption peaks occurred at UV region for all resin tested. The total power density of halogen and LED units (454±7 and 470±8mW/cm², respectively) showed no significant difference (p=0.055). Relatives CP_360-550nm calculated from halogen and LED for each resin was, respectively: ADP (239±8 and 378±10); CFL (37±2 and 27±1); SEB (44±2 and 26±1); FTS (88±3 and 92±3); UXT (53±2 and 56±3). Conclusions: Lights performed similar for composite resins but not for adhesives tested. Maximum absorption at UV region indicates photoinitiators different than CQ such as PPD and acylphosphine oxides. ADP and FTS contain acylphosphine oxide as photoinitiator (manufacturer information) which probably contributed to higher CP values. CFL and SEB are self-etching primers with similar potential for cure regardless the light used.