Birch polypore (Piptoporus betulinus) has been used medicinally by many cultures for centuries. Recently, compounds extracted from this fungus have been shown to have anticancer activities, prompting an interest in cultivation. However, birch polypore only fruits seasonally and is difficult to cultivate, with only one study describing indoor cultivation success. Improving indoor cultivation techniques will allow for greater harvests increasing the production of medicinal compounds for medicinal research. My research was designed to refine the current indoor cultivation method developed in Poland to improve the biological efficiency (amount of fruit biomass per unit substrate), by manipulating levels of nitrogen supplementation to the substrate. Several specimens of birch polypore were collected in November 2016 in Pisgah NF. Cultures were created by excising pieces of internal tissue and transferring them onto malt extract agar medium plates. Once fully colonized, kernel size portions of cultures were transferred into bags containing sterilized rye grain to create inoculum. For each replicate 0.7 kg of kiln-dried birch (Betula sp.) sawdust and chips substrate will be mixed with conditioning materials (dolomite, gypsum and sucrose) and placed in microporous-filtered polypropylene bags. Bags will be assigned to nitrogen supplement (a mix of 60% rice bran, 20% soy powder and 20% rye flour) treatment of 0%, 10%, 25% and 50% of substrate dry mass with 5 replicates for each treatment. After autoclaving, each bag will then be inoculated with 20 grams of inoculum, sealed and placed in constant temperature (25oC) growth chambers. Once bags demonstrate thorough mycelium development, they will be cold shocked (2–4 °C for 48 hours). Upon reaching maturity the fruiting bodies will be harvested, dried, and weighed to determine biological efficiency. I predict increasing biological efficiency in fruiting body production with increasing nitrogen additions and predict biological efficiencies greater than 16% at the highest level.