Objective: This study aims to chemically characterize the compost resulting from fish filleting waste, identifying macro and micronutrients, and investigating the effects of different dosages of this compost on lettuce fertilization. Theoretical Framework: The research is based on concepts of sustainable management of urban solid waste, highlighting composting as an effective practice for recycling organic matter. Previous studies on composting animal waste and its application underpin the context of the research. Method: The methodology consisted of experiments with 28 plants, applying 7 treatments with 4 replications, ranging from 10% to 50% fish compost. Fresh and dry mass, root size and volume, and nutrients were analyzed. Results and Discussion: The results indicated that fish waste compost has significant potential as a source of nutrients, with medium to high levels of macro and micronutrients. In lettuce cultivation, the 10% dosage was the most cost-effective, although proportions of up to 30% promoted good development in all the indicators evaluated. Research Implications: The practical implications of this research suggest that fish waste compost could be a viable alternative for organic fertilization, promoting sustainable practices in waste management and agricultural production. Originality/Value: This study contributes to the literature by exploring the use of fish filleting waste compost as a fertilizer, demonstrating its effectiveness and potential as a source of nutrients for lettuce cultivation.