Introduction: Primary hypertension is regarded to be a growing health concern in children. The pathogenesis of primary hypertension is multifactorial. The role of altered levels of matrix metalloproteinases has been proposed. In hypertension, metalloproteinases are engaged not only in vascular remodelling but also in activation of vasoconstrictive agents. Aim of the study: We aimed at comparing the serum concentrations of matrix metalloproteinases-2, -3 and -9, and tissue inhibitor of metalloproteinases-1 in children with primary hypertension and normotensive peers. Materials and methods: We surveyed 23 children with primary hypertension, aged 14.75 years (median; interquartile range, IQR 3.66) and 23 normotensive subjects, aged 14.66 years (median; IQR 6.25). Serum concentrations of matrix metalloproteinases-2, -3 and -9, and tissue inhibitor of metalloproteinases-1 were measured using enzyme-linked immunosorbent method, and the scores were compared with Mann–Whitney U test, with the level of significance at p ≤ 0.05. Results: In children with primary hypertension, serum concentration of matrix metalloproteinase-2 [178.1 (IQR: 35.84) vs. 99.9 (IQR: 20.1) ng/mL], -3 [6.47 (IQR: 1.75) vs. 2.67 (IQR: 1.08) ng/mL], -9 [191.1 (IQR: 52.75) vs. 58.34 (IQR: 18.99) ng/mL] and tissue inhibitor of metalloproteinases-1 [863.9 (IQR: 192.9) vs. 335.41 (IQR: 109.99) ng/mL] were significantly higher than in the normotensive controls (p < 0.00001). Matrix metalloproteinase-9/tissue inhibitor of metalloproteinases-1 ratio [0.22 (IQR: 0.1) vs. 0.18 (IQR: 0.05)] was also significantly elevated in the hypertensive participants (p = 0.008). Conclusions: Elevated serum concentrations of matrix metalloproteinases-2, -3 and -9, and tissue inhibitor of metalloproteinases-1 in children with primary hypertension may indicate their role in the development of hypertension and/or on the presence of vascular remodelling at an early stage of the disease.