This study evaluated the effects of corncob as a source of insoluble fibre and xylanase enzyme on broiler chicken performance, ileal digestibility, intestinal morphology, gastrointestinal pH, and serum biochemical traits. Two hundred fifty six 1-day-old (Ross 308) broiler chicks were randomly given six diets for 24 days: a control diet with 0%, 2.5%, or 5% corncob, with or without xylanase, in a 3 × 2 factorial arrangement. Then, chicks were given the control diet with or without xylanase until they reached 42 days. Adding corncob to diets reduced performance during the grower phase (P ≤ 0.05), but when removed, the performance did not differ from the control (P ≥ 0.05). Corncob reduced ash digestibility and cholesterol levels (P ≤ 0.05) while increasing the relative weight of the heart, gizzard, and duodenum and improving the ileal villus high-to-crypt depth ratio (P ≤ 0.05). The feed conversion ratio increased due to corncob inclusion in diets at the starter and grower phases (P ≤ 0.05) but did not differ from the control at the finisher phase. Xylanase supplementation improved performance, nutrient digestibility, intestinal histomorphology, and reduced cecum weight with digestive tract pH (P ≤ 0.05). Therefore, adding corncob with xylanase enzyme to broiler chickens’ diet does not negatively impact their performance. On the contrary, it improves the broilers’ health and reduces production costs.