Presently, the animal feed industry is suffering from inadequate and expensive conventional protein ingredients due to the increasing demand for food and feed products. This has led to the search for unconventional protein sources to fulfil market needs. In this study, the potential of selected palm oil wastes, namely palm pressed fibre (PPF) and palm oil decanter cake for bioprotein production, was investigated. Fermentation process was carried out aerobically in conical flasks with the working mass of 20 g each at 32°C for seven days. The performance of these palm oil wastes as substrates in solid state bioconversion of Aspergillus terreus UniMAP AA-1 strain were evaluated. A substrate with higher protein yield was chosen for the subsequent parameter screening using 2-level factorial design. Results showed that the protein content in PPF and palm oil decanter cake was increased up to 401 mg/L and 493 mg/L, respectively post-fermentation. Among the parameters studied, substrate concentration and inoculum size were found to significant affect bioprotein production. The highest protein content of 1683 mg/L was successfully produced from palm oil decanter cake at temperature of 35°C with 50% substrate concentration and 15% of inoculum size, suggesting its potential as an alternative protein source. Thus, this study provides preliminary data for future process optimisation of bioprotein production using the statistical approach.