This paper describes an operational subsea wireline system that is self-contained and flexible and offers a safe, economical, and proven method for riserless re-entry into any subsea well. IntroductionApproximately 400 subsea wells currently exist worldwide, and most predictions indicate a doubling of this number within the next decade.Being time-consuming and costly, conventional methods of reentering subsea wells with wireline are not consistent with the lowcost profile required by many subsea developments. This factor has predominantly driven the development of cost-effective subsea wireline systems.The system discussed here was developed over a number of years and has been used to carry out a comprehensive range of wireline tasks from floating vessels in the North Sea. Although generally deployed from a diving support vessel (DSV), the system has been successfully used from a drilling rig to conduct wireline operations in a well, simultaneously with workover operations in an adjacent well, on a subsea template.It is important to realize that any function that can be achieved by conventional means can also be carried out by subsea wireline. Subsea wireline has been used to pull and run surface-:controlled subsurface safety valves (SCSSV's), to set and pull plugs, to pull and run gas-lift valves in side-pocket mandrels, and to run production logging tools and electronic memory recorders.