The article provides a brief overview of the Polish law of obligations. In particular, the main sources of obligations are briefly presented, i. e., contracts, torts and unjust enrichment. Special attention is paid to mutual obligations, joint and several obligations, pecuniary obligations and obligations deriving from consumer contracts. The article discusses the legal instrument for concluding a contract such as preliminary contract, and also performance, discharge and remedies for breach of contract. In particular, the consequences of delay in the performance of an obligation and the types of such delay are considered. The author pays special attention to the issues of liability for non-performance of obligations, in particular, compensation for losses from non-performance. The article reveals the content of the pacta sunt servanda principle in Polish law and the existing exceptions to this rule. Such a method for the termination of an obligation is specifically considered, in addition to its performance, as a set-off. The author presents different measures that may discipline the parties to perform the obligation, such as contractual penalties and earnest money deposit. Finally, the article addresses the notion of damage, principles of liability and obligation to compensate. When describing the obligations from unjustified enrichment, special attention is paid to the fact that the loss of enrichment excludes its reclamation from the enriched person if he lost the enrichment without knowing about the obligation’s existence. In regard to tort law, it is emphasized that there are cases of innocent liability for causing harm in Polish law as an exception to the general rule. Only illegal actions or omissions can be qualified as guilty and entail responsibility. Polish law does not recognize the general obligation to refrain from causing harm. The culpability of misconduct is presumed. In some cases, the behavior cannot be recognized as illegal, even if it violates the general prohibition established by law. In particular, this concerns causing harm in the case of necessary defense, extreme necessity, permissible self-help and in a number of other cases.