The acidity of olive oil samples from different locations and of different storage ages was measured on a yearly and weekly basis. In this work, the overall results of olive oil acidity as a function of storage age on a yearly basis indicate deterioration of oil quality. The acidity results for some olive oil samples suggest that the oil can be stored for a period of not more than 12 years without deterioration. The overall results from measuring on a weekly basis indicate that the acidity increases incrementally as a function of storage age. The relationships between the acidity and storage age were described by fitting the data to equations.