Human factors is the study of the interaction of people and technology to ensure that a good compatability exists between the human beings and the device,manufactured to address a disorder or a condition. In addition to that, it provides safety and efficacy to that interaction which includes the user interface, instructions,and training programs to avoid or minimize the errors. In the recent times, more attention is being paid to the assessment of the human factors usability for the combination products by obtaining the acknowledgement by regulators and industry regarding the mechanics of the device about its reliability and its usability.Usually the errors occur when the device is not used as intended or some features of the design are not optimal. Human factors testing, analysis, and validation helps in identifying and eliminating those errors after using appropriate mitigation strategies to ensure the device design provides the optimum use of drug/device combination products.