The Atlantic Forest is an important biome formed by different phytophysionomy and is considered a hot spot of biodiversity. Some parts of the biome has received more attention in recent studies but few articles has stood out in the physiognomy of nebular forest, especially in peri-urban forests. The objective of this study was to evaluate soil fertility and litterfall production and decomposition in a peri-urban forest of São Paulo city, Brazil. The studied area is located at the Curucutu nucleus, at the State Park of Serra do Mar, southern of São Paulo city. The phytofisignomy is characterized by dense broadleaf vegetation in a nebular forest. Five different points were selected in 1 ha plot to collect soil samples at 0-10, 10-20, 20-30 cm depths to analyze physicochemical properties. For analysing litterfall production 20 litter traps were randomly distributed in the plot. After collected, the material was dried and weighted. For decomposition, sixty litter bags were randomly placed on the soil and 12 of them were monthly collected to assess the biomass loss. The results indicated low nutrient availability and high values of aluminum in the soil due to extremely acidic conditions. The soil C:N, C:P and P:N ratios showed an inefficiency in nutrient cycling probably due to the slow decomposition rate, which probably contributed to low availability of nutrients. Litterfall production reached the amount of 6.4 Mg ha-1 year-1 with the highest production during the spring and summer. The litter bags methodology confirmed the lower decomposition rates and the time to decompose 50% and 95% of the material was higher than the expected for fragments of the Atlantic forests. The low values of macro and micronutrients verified, associated with the acidity and the presence of toxic element, affect the fertility of the soil at the Curucutu, resulting in nutritional deficiencies to the existing vegetation.