This study aims to evaluate the diagnostic accuracy of preoperative computed tomography (CT) and intraoperative endoscopic tumor staging with regard to histopathologic staging in patients with early laryngeal cancer. A retrospective nonrandomized single-institution comparative cohort study including 109 patients. A tertiary surgical center. Patients were treated for T1a, T1b, and T2a laryngeal squamous cell carcinoma by endoscopic laser surgery. The outcome measures were the presence of under- or overstaging in endoscopic and CT findings and positive postoperative margins. Endoscopic overstaging as compared with histopathologic T category correlated with rising tumor category (P = .001; odds ratio [OR], 69.1) and CT findings showing anterior commissure involvement (P = .002; OR, 9.54), while endoscopic understaging correlated with rising tumor histologic grade (P = .039; OR, 4.28) and smaller tumor size (P = .011; OR, 6.39). CT overstaging vs histopathologic T category correlated with CT findings showing anterior commissure involvement (P = .001; OR, 21.76), supraglottic involvement (P = .001; OR, 59.98), subglottic involvement (P = .001; OR, 39.94), rising clinical T category (P = .01; OR, 9.11), and rising tumor histologic grade (P = .004; OR, 10.95). CT understaging as compared with histopathologic T category correlated with smaller clinical T categories (P = .002; OR, 12.72) and smaller tumor histologic grade (P = .030; OR, 7.02). Rising age, rising tumor size, anterior commissure involvement on CT, and tumor extension into the supraglottis were risk factors for positive margins. Our results indicate that CT adds little valuable information in differentiating small superficial lesions in the glottis, while systematically overstaging cases of early laryngeal cancer. In T1a and T1b glottic tumors, endoscopy should be the preferred diagnostic method.