A rubrene-based nanostructure has been prepared by applying the evaporation method at room temperature. The Co-60 gamma-ray irradiation effects on the electrical properties of the rubrene nanostructure were also examined by measuring current-voltage values. Standard, Norde, and Cheung methods have been used to obtain series resistance, interface states, barrier height, and an ideality factor before and after gamma rays. After obtaining the required information from these methods, they have been compared with each other before and after irradiation. The behavior of barrier height is dependent on the evaluated methods. Cheung, Standard, and Norde functions are different from each other owing to extraction from different regions of the plots. It has also been revealed that the ideality factor values for all the methods decrease with irradiation as do the electrical properties, such as series resistance evaluated using Norde and Cheung methods. These two methods give the same results. All the methods revealed that the series resistance values increase with irradiation. Further, these parameters are dependent on the strong functions of voltage.