Point-of-care testing (POCT) is highly desirable for early detection of infectious diseases; however, current molecular diagnostics require a series of sophisticated facilities and instruments, which critically limits its direct application to POCT. From this perspective, chip-scale microfluidic technologies have been widely investigated to provide rapid, low-cost POCT diagnostics. Despite the development of small-footprint portable microfluidic chips for molecular diagnostics, the integration of functional steps into POCT is still a crucial, unsolved issue to be addressed. Herein, we suggest an all-in-one pumpless portable genetic analysis microsystem for molecular diagnostics with facile and portable operation by suggesting three main functions: (i) a finger-powered actuator for exquisite fluid control, (ii) a poly(dimethylaminomethyl styrene)-based polymeric surface for efficient nucleic acid harvest and extraction, and (iii) loop-mediated isothermal amplification-based amplification and colorimetric detection. The developed system can be stored at room temperature, shows a wide detection range from 1 x 103 to 1 x 107 cells, and enables naked-eye detection with a total detection time of less than 80 min. This allin-one pumpless portable genetic analysis microsystem can be utilized as a simple and accurate platform for POCT diagnostics.