The attractive nuisance doctrine is a premises liability theory—a legal basis on which the owner or operator of real property (premises) may be liable for personal injuries suffered by a child who trespasses on the premises and is injured by an object that attracted the child onto the premises—such as a swimming pool; a playground slide; a trampoline; piles of wood or sand; or abandoned machinery, equipment, or motor vehicles.

The only duty a premises owner or occupier owes a trespasser is not to injure him willfully, wantonly, or through gross negligence. But as to invitees, a premises owner or occupier must use ordinary care to reduce or eliminate an unreasonable risk of harm created by a premises condition of which the owner is or reasonably should be aware.

But when children of tender years come upon the premises by virtue of their unusual attractiveness, the legal effect is that of an implied invitation to do so. Such child is regarded, not as a trespasser, but as being rightfully on the premises. This is the doctrine of attractive nuisance. It originally developed in so-called “turntable cases” where young children were injured playing on railroad turntables which seemed especially attractive playgrounds, the dangers of which children did not appreciate.

Thus, a possessor of land is subject to liability for physical harm to children trespassing thereon caused by an artificial condition upon the land if:

• the place where the condition exists is one upon which the possessor knows or has reason to know that children are likely to trespass, and

• the condition is one of which the possessor knows or has reason to know and which he realizes or should realize will involve an unreasonable risk of death or serious bodily harm to such children, and

• the children because of their youth do not discover the condition or realize the risk involved in intermeddling with it or in coming within the area made dangerous by it, and

• the utility to the possessor of maintaining the condition and the burden of eliminating the danger are slight as compared with the risk to children involved, and

• the possessor fails to exercise reasonable care to eliminate the danger or otherwise to protect the children.

Laws vary from state to state and not all states recognize the attractive nuisance doctrine. In states that do recognize the attractive nuisance doctrine, the law may be located in the state’s court opinions—also known as the common law or case law—or in the state’s statutes.

In Colorado, the attractive nuisance doctrine is recognized and can be a basis for premises liability when a child trespasses and is injured by a hazardous object or condition on someone's property. This doctrine holds property owners or occupiers liable for injuries to children caused by artificial conditions on their land that are likely to attract children, who due to their age may not recognize the risks. The conditions for liability include the owner's knowledge of children likely to trespass, the unreasonable risk posed by the condition, the child's inability to appreciate the risk, the relatively minor burden on the owner to remedy the situation compared to the risk to children, and the owner's failure to take reasonable steps to protect children. This doctrine is part of Colorado's common law, derived from court decisions rather than specific statutes. Property owners must therefore exercise ordinary care to prevent harm to children who might be attracted to dangerous conditions on their property.