The master's thesis "Analysis of Media Influence on the Corrosion Behavior of Low-Alloy Steel" investigates the corrosion mechanisms of low-alloy steel in various environments. The thesis consists of a theoretical and experimental part. The theoretical section focuses on electrochemical and chemical corrosion, identifies their fundamental differences, and studies the influence of media on material behavior. It also describes other classifications of corrosion processes as well as appropriate protection methods. Additionally, the thesis analyzes internal and external factors that affect the corrosion of low-alloy steel. Changes in the material's internal properties and isolation from aggressive media can enhance material resistance to corrosion. In the experimental section, electrochemical testing of corrosion rate was conducted considering different mediums. The steel 51CrV4 was used as the tested sample, known for its high strength, hardness, good resistance to wear and abrasion, as well as its high toughness and ease of heat treatment. During the heat treatment, the steel was quenched first and then tempered at 600 °C. The experimental investigation was performed in various NaCl solutions to analyze this impact. The concentration of NaCl solution proved to be a significant factor in the corrosion behavior of low-alloy steel. Samples immersed in higher concentration solutions exhibited an increased corrosion rate compared to samples in lower concentration, which can be valuable in the context of material selection for specific environmental conditions to avoid excessive corrosion.