Background: A validated method based on capillary zone electrophoresis coupled with a diode array detector (CZE-DAD) was investigatedfor analyzing binary mixture of ibuprofen (IBU) andphenylephrine (PHE) in their bulk and combined dosage form. Objective: This binary mixture is a challenging one as IBU is acidic and PHEis alkaline, which may affect their simultaneous analysis using CZE. The literature lacks any CZE report for IBU and PHE simultaneous analysis. Methods: Fused silica capillary (85 cm × 75 μm id) was used, and the electrolyte was a 50 mM borate buffer adjusted to pH 11 with 0.5 M NaOH. Results: The concentration ranges were 5–200 and 5–100 μg/mL for IBU and PHE, respectively, using CZE. High efficiency was achieved (N > 92990). Reasonable migration time (t_m) was attained (t_m< 8.5 min). Conclusions: Although the results obtained by the proposed CZE method and reported HPLC method were statistically comparable, the proposed method showed lower linearity ranges, higher efficiency, and a more reasonable run time. Highlights: CZE-DAD was used for the analysis of IBU and PHE in bulk and tablets, as no report was foundfor their determination using CZE. Binary mixture is challenging due to differences in chemical and physical properties. A detailed discussion of electrophoretic parameters optimization is included. Confirmation of peak purity was attained using DAD.