Introduction and objective: Alpha-1-antitrypsin deficiency is a common inherited metabolic disorder. Deficiency of this serine protease inhibitor predisposes to progressive tissue damage, primarily affecting the lungs and liver. In children, the clinical presentation is heterogeneous and may extend beyond classical organ involvement. The aim of this study was to assess the relationship between serum alpha-1-antitrypsin levels and individual clinical manifestations in children with confirmed alpha-1-antitrypsin deficiency. Materials and methods: A retrospective analysis of medical records was performed in 18 patients (nine girls, nine boys) aged 1–17 years. In all cases, serum alpha-1-antitrypsin concentration was measured, and SERPINA1 genotyping was performed. Clinical data, liver enzyme activity (aspartate aminotransferase, alanine aminotransferase), and family history were analysed. Results: The PIMZ genotype was identified in 94.4% and the PISZ genotype in 5.6% of patients. The median serum alpha-1-antitrypsin concentration was 79.0 mg/dL (range 61–96 mg/dL). The most common clinical features in the study group were recurrent respiratory tract infections (72.2%), inhalant allergy (61.1%), recurrent otitis media (38.9%), and food allergy (33.3%). Hepatic manifestations were observed in 27.8% of patients, and asthma in 22.2%. Lower alpha-1-antitrypsin levels correlated with early-onset asthma (67.5 vs. 80.0 mg/dL; p = 0.017). A positive family history was reported in seven patients (38.9%). Conclusions: Alpha-1-antitrypsin deficiency in children is characterised by a heterogeneous clinical presentation, with predominant respiratory and hepatic involvement. It should therefore be considered in the differential diagnosis of children presenting with atypical or recurrent respiratory or hepatic disorders. Although atopic conditions were frequently observed, their relationship with alpha-1-antitrypsin deficiency remains unclear and warrants further investigation.