Background and objectives: Hypertension is a disease affecting a large part of the world's population that causes millions of deaths annually. Physical exercise is proposed as an alternative to pharmacologic therapies used to reduce blood pressure. The main objective was to compare the effect of different types of strength training in blood pressure, as well as to analyse several variables that can modify the effect of strength training not combined with medication in SBP and DBP (SBP-DBP). Methods: The search was carried out in two scientific databases: PubMed and Web of Science. Articles were included following three criteria: analysing the chronic effect of strength training in blood pressure; the studies were conducted at least during 4 weeks; and the articles were published in English. Results: The analysis showed a significant decrease of blood pressure for all types of training. The effect on SBP was greater when training without medication was carried out with isometric exercises than when training was performed with dynamic exercises. Moreover, the effects were no longer significant when the duration of the training programme exceeded 20 weeks as well as when training frequency was lower than three times per week were found. Conclusion: Strength training is effective in reducing both blood pressures (SBP-DBP). Training programmes, consisting of dynamic strength training without medication at a moderate intensity and with a frequency of three times per week, seem to be optimal in order to reduce blood pressure.Prospective register of Systematic Reviews: CRD42019122421.