Background: Preseptal and orbital cellulitis are two types of infection surrounding the orbital septum with very different potential outcomes. Our aim was to describe key differential features of both conditions, laying special emphasis on diagnostic and therapeutic tools. Methods: A retrospective review of patients admitted to a tertiary hospital over a 15-year period (January 2004-October 2019) was conducted. We included 198 patients with preseptal and 45 with orbital cellulitis. Descriptive statistics were performed to examine the available information. Results: Statistically significant differences were found between patients with preseptal and orbital cellulitis regarding age (3.9 ± 2.14 vs. 7.5 ± 4.24 years), presence of fever (51.5% vs. 82.2%), and preexisting sinusitis (2% vs. 77.8%) (all P < 0.001). Diplopia, ophthalmoplegia and proptosis were only present in orbital cellulitis (P < 0.001). Median values of C-reactive protein were significantly higher among children with orbital involvement [136.35 mg/L (IQR 74.08-168.98) vs. 17.85 (IQR 6.33-50.10), P < 0.0001]. A CRP>120 mg/L cut-off point for orbital cellulitis was obtained. Early CT scans were performed in 75.6% of suspected orbital cellulitis and helped detecting complications at an early stage. Abscesses were revealed in 70.6% of cases, especially medial subperiosteal abscesses (58.8%). All patients received intravenous antibiotics, whereas corticosteroids were preferred in patients with orbital implication (8.6% vs. 73.3%, P < 0.001). Only 26.7% of patients required additional surgery. Conclusions: Clinical presentation and CRP are extremely sensitive for differential diagnosis of preseptal and orbital cellulitis. Prompt initiation of intravenous antibiotics is mandatory and can prevent surgical procedures even in cases with incipient abscesses.