The Czech professional divers association The Czech professional divers association emerged in 1993 as an Association of businessmen, instructors and professional workers in commercial diving. Its goal is, in collaboration with Association of divers in the Czech Republic, to develop and popularise professional diving and to allow applicants to gain a Diver’s profession card with international effect. Our country has a diving tradition that is around 40 years old. By that time was works under water made mostly by volunteers from water management employees or Banish rescuers.    The name “a professional diver” means someone who engages in this kind of activity, owns a divers professional card or another professional diving license, for example: IMCA or someone who is in training in a Professional diving school. Professional divers association published a directive for working diving; this modifies requirements for working under water and basically states the rules that come from the directives of working diving in some states of the European Union and Canada. Among professional divers it is possible to include professional instructors who train sporting and technical diving but instead belong to sporting activities. The main difference between professional, industrial and sporting or technical diving is in the goals of each of these activities. While the sporting and technical divers want to dive somewhere, to dive and come up, for the professional or industrial divers, diving is merely a way to fulfil their working requirements. There are many working activities under water and it is possible to separate them into a few main groups: building tasks – work of mechanical character – rescue missions and exploratory and control tasks. In the Czech Republic industrial divers work under water for about 4000 hours. Seeing that many divers do industrial diving, on average an industrial diver spends about 350 hours per year under water. The most common activity is that of repairing water management works. It can consist of fixing weir mechanisms, welding steel constructions; some assemble works or just control and explore works. Next ‘favourite’ activity of divers is removing alluviums. Favourite is in inverted commas, because it depends on the kind of material that is being removed. Intake racks catch everything possible, from sharp rust-stained sheets, rotten wood, and plants, to oil drums and rubbish of all kinds. Divers have to use their own hands, because it is not possible to use heavy machinery. At the most of diving - industrial works under water can divers see just few centimetres before them, in better cases on tens of centimetres, but just until the works start. After start can divers see nothing. In these cases is necessary to follow senses of touch and hands are becoming eyes of divers. Among next activities belong building works. From simple exhaust of alluviums to very complicated buildings and reconstructions of ferro-concrete constructions. It appears from this that besides a diver’s profession permit they must have special authorization needed for works under water like: authorization for welding under water, burning constructions under water, binding load etc. Differences between sporting and industrial diving are in used instrumentation. The main difference is that of the supply of oxygen. In industrial diving uses a surface supply, which secures enough oxygen for unlimited time for cases of sticking or detainment. Divers are not stressed in these cases neither endangered by a limited supply of oxygen in their oxygen tanks. The supply in oxygen tanks witch divers have under the water is just a safety precaution/reserve. In industrial diving it is commonplace for permanent telephone communication thanks to a cable telephone, because sonographic telephones do not work in some cases and it is not possible to depend on them. It is very useful to use helm cameras, as they allow permanent broadcast of scene in real time, including recording sound and picture but a sufficient transparency of water is needed. These cameras are possible to use for seeing inaccessible places for divers. The structure of breathing mixture is almost the same in both kinds of diving. For submersions down to 50 meters air is used. For submersions of about 30 meters it is better to use NITROX, this gas allows time to be used more effectively in proportion work/emersion. For submersions lower than 50 meters helium mixtures are used. The changes of breathing gases for working in depth, emersion and decompression procedures, directed by operators on the surface. Diver in a hard and stress workspace, in zero visibility and limited space do not have to worry about which kind of gas has to be used in which depth. Submersions are often under way in places that cannot be named as water. For example dung-water, whitewash, oil tanks, reservoirs of sewage disposal plant or liquid clay. These submersions are in the care of the team on the surface. For emersion and decompression procedures NITROX and OXYGEN are used as standard. For heavy depth works a safety decompression bell is used with communication and a source of oxygen. Industrial divers usually wear head sets. They cover the head perfectly, are comfortable, allow good communication, have many systems of breathing gas source and give enough protection in unwholesome water. Light sets with supply of breathing gas carried by diver are not used very often, for example for controls. For industrial diving a diver goes under water on very rare occasions alone. Therefore he has to rely on his team that cares about diver safety and progress of submersion. The diver can therefore pay all his attention to fulfil his work. Professional – industrial diving is primarily teamwork. Miloslav Haták Chief diver of Diving station, Instructor of commercial diving, 3900 hours under water, 33 years of experience in commercial diving