The Covid-19 pandemic is a crisis that affects the economy and, more importantly, aeffcts the food and agricultural sector. This study determined the mycelial growth activity of Pleurotus ostreatus using indigenous root crops as an alternative culture media. The study was conducted at the ASIST Tissue Culture Laboratory located at the Research and Development Building, Poblacion, Lagangilang, Abra. This study adopted the experimental-evaluative method. The highest mean on the growth of P. ostreatus mycelia was presented by Tigi (TMA) compared to other alternative culture media in terms of radius after seven days of incubation. (2) The highest degree of mycelial density of P. ostreatus was exhibited by Tigi (TMA) compared to other alternative culture media. (3) There was a significant difference in the growth of mycelia between the alternative culture media and the control standard PDA media. The following recommendations are provided: (1) Utilize Tigi or elephant foot yam as a substitute raw material in preparing alternative culture media for P. ostreatus. (2) On mycelial density, tigi (TMA) exhibited the highest degree, kamangeg (KMA) and potato (PDA) displayed intermediate degree. Kamangeg or wild yam can be evaluated further as an alternative media for P. ostreatus mycelial production. (3) Another indigenous root crop is recommended for further evaluation as an alternative culture media for mycelial production.