This was announced by Presidential Administration press service, Censor.NET reports.
The head of state said the signed document is a part of the judicial reform aimed at enforcement of Ukrainian citizens' right for fair trial.
The president stressed two important innovations stipulated by the Law.
"[It's] absolutely transparent competitive selection of judge candidates to Constitutional Court," the head of state said.
The president said everyone will be able to learn more about any candidate.
The second innovation is that any legal entity (except for state representatives and local government) or individual will be able to file a claim to the Constitutional Court. The head of state said never in Ukraine's history an ordinary citizen was able to do that.
"If a person, after having his/her case considered in ordinary courts, believes that the law that was applied when deciding on it is unconstitutional, then he/she should no longer seek people's deputies or the president. He/She will finally have the right to directly appeal to the Constitutional Court with a constitutional complaint, and the court must consider it and make an appropriate decision," the head of state said.
The president added: "I think this significantly increases the level of protection of constitutional rights and freedoms of citizens."
Petro Poroshenko thanked the MPs for supporting the presidential proposals considered in the Law.