In this master thesis the lawsuit over ownership, which is based on the Act on Ownership and Other Real Rights, is analysed and compared. The owner uses the lawsuits over ownership in order to protect himself in case of someone depriving him of his object or holding it illegally in his possession. In this case the owner could file a real lawsuit over ownership for the return of objects (rei vindicatio) or if someone would illegally disturb the ownership right in some other way, but if the object is not deprived yet, he could file a real lawsuit over ownership in order to stop the disturbance. During attestation, it is important that the owner can prove his real ownership and that his object is in possession of other person without legal basis. If he succeeds to prove it he could file a real lawsuit, while for actio publiciana one needs to prove that the owner has stronger right of possession. In this master thesis, it is also analysed that in every ownership lawsuit exists the legal position of the owner as suitor and the possessor as defendant. Further, if the possessor is fair or unfair depends on the objections, claims and counterclaims, which the owner and possessor can make. The relevant judical practice related to the protection of the ownership right is also mentioned in this paper.