A socio-environmental assessment on the installation of relay antennas in the city of Mbandaka, and their toxic effects on human health, was carried out in the districts of Mbandaka and its surroundings, in the province of Equateur, in the Democratic Republic of Congo. In these districts, the installation of relay antennas is done without respecting the standards in terms of communication. The field study revealed that the proliferation of relay antennas in the city of Mbandaka and its surroundings did not respect environmental standards, and this caused most cardiovascular diseases in the surrounding population. The results obtained show that: - No environmental impact study was carried out before the installation of these relay antennas. - 75% of the population uses mobile phones which makes this device the first advanced communication tool to be used. - 85% of relay antennas are installed less than 20 meters from residential houses. - 95% of respondents are ignorant of the danger of relay antennas. - The Environmental Impact Study did not take place before the installation of these relay antennas. - Most of the illnesses observed in the surrounding health structures are due to non-compliance with established standards for the installation of relay antennas. - 96% of GSM antenna sites located in Mbandakan did not comply with standards.