Sesame (Sesamum indicum L.) is one of the most important and ancient oilseed crops valued for its high-quality edible oil, nutritional properties, and economic importance. Sesame is an excellent source of vegetable oil, and is known as the "queen of oil seeds" due to its high oil content with unsaturated fatty acids, proteins and carbohydrates. However, its productivity is constrained by several foliar diseases, particularly bacterial blight and Cercospora leaf spot, which are widely distributed in Ethiopia. The experiment evaluated 64 sesame genotypes to identify sources of resistance and high-yielding lines under natural disease pressure at Bako Agricultural Research Center in Western Ethiopia. The trial was conducted using an alpha lattice design with two replications. Two rows for one intery genotype with three replications and one block containing eight genotypes. Disease severity was assessed on eight tagged plants per plot using a 0–6 scale for bacterial blight and a 0–5 scale for Cercospora leaf spot, and converted into a percentage severity index (PSI). The area under the disease progress curve (AUDPC) was computed. Significant (p < 0.01) variation was observed among genotypes for disease severity, AUDPC, and grain yield. Final bacterial blight severity ranged from 9.0% to 41.2%, while Cercospora severity ranged from 5.0% to 33.2%. Several genotypes (e.g., SE42, SE51.4, SE14, SE39.1, SE49.1, SE4.1) exhibited strong resistance to one or both diseases. Yield varied widely, with SE42.1 (1039 kg ha⁻¹), SE20.2 (973.9 kg ha⁻¹), and SE54.2 (960.4 kg ha⁻¹) being the top performers. These genotypes represent promising candidates for breeding programs aimed at developing high-yielding and disease-resistant sesame varieties.