The impact of microplastics (MPs) on carbon (C) and nitrogen (N) content in vermicompost is not yet fully understood. This study aims to evaluate the effect of MPs on the carbon and nitrogen ratio in vermicompost, which is important for soil quality and health. The study was carried out using a control treatment and six variations of MPs in the vermicomposting process. Observations were carried out at certain time intervals for 60 days with routine measurements of pH, electrical conductivity (EC), seed germination index (GI), survival rate (SR), and C/N ratio. The results showed that all types of MPs caused a decrease in the C/N ratio compared to the control, with the high‐density polyethylene (HDPE) MPs treatment showing the most significant decrease (from 21 to 9.42). Observations also showed that MPs had an impact on reducing the SR parameters (6.88%–20.41%), pH (6.8–6.1), and EC (525.3–398 µs/cm) in vermicompost, which had an impact on the final product quality thereby reducing the GI (10%–28%). MPs have a significant effect on the C/N ratio in vermicompost, reducing the quality of the compost. This study provides new insights into how MPs can affect the composting process and the quality of the final product, important for sustainable agricultural practices and waste management.