Introduction: The food industry uses synthetic preservatives in order to extend the shelf life of products and avoid their deterioration. However, some of these preservatives can affect people__ampersandsignrsquo;s health. In order to counteract this, industries are replacing them with those of vegetable origin. Guava is one option, because of its bioactive compounds. Objective: The purpose of this study was to substitute synthetic preservatives with natural compounds to offer consumers a high-quality product that guarantees their health. Method: This study evaluated the effect of seven concentrations of guava essential oils and ascorbic acid on the microbial activity (Staphylococcus aureus, Escherichia coli and Salmonella) of Frankfurter-style chicken sausages over a period of 30 days. Therefore, finding a viable solution to reduce the contamination levels of Frankfurter-style chicken sausages and to propose a natural alternative as preservative in these meat products. The collected data was analysed by means of ANOVA. Results: Of the results obtained, the application of 1000 ppm of guava essential oil alone or in combination with 700 ppm of ascorbic acid was best at inhibiting the presence of these microorganisms in the sausages, compared with the synthetic preservative (BHT). Conclusion: It is important to mention that the number of microorganisms present in the sausages were within the ranges stipulated by Ecuadorian regulations. Therefore, the obtained results demonstrated the potential of guava essential oil (Psidium guajava L) in the processed food industry, constituting a viable alternative to replace those of artificial origin.