Short answer. Yes. A penalty imposed by a final sentence can prescribe, meaning the State loses the power to make the convict serve it. The Revised Penal Code fixes the periods by how grave the penalty is, running from twenty years down to one year for light penalties.
What the law says
The penalties imposed by final sentence prescribe as follows: 1. Death and reclusion perpetua, in twenty years; 2. Other afflictive penalties, in fifteen years; 3. Correctional penalties, in ten years; with the exception of the penalty of arresto mayor, which prescribes in five years; 4. Light penalties, in one year.
Revised Penal Code, Article 92 — When Penalties Prescribe. Read the full provision →
Two different clocks: the crime and the penalty
People often confuse two separate rules. One governs how long the State has to file a case after the crime; the other governs how long it has to enforce a penalty already imposed by a judgment that has become final. Article 92 is about the second. It assumes the trial is over, the conviction stands, and the only thing left is service of the sentence. If the convicted person was never taken into custody, or escaped after being taken in, the law does not let the sentence hang over him forever. It runs a clock, and when that clock finishes, the penalty is extinguished.
How long each penalty lasts before it prescribes
The statute reads: The penalties imposed by final sentence prescribe as follows: 1. Death and reclusion perpetua, in twenty years; 2. Other afflictive penalties, in fifteen years; 3. Correctional penalties, in ten years; with the exception of the penalty of arresto mayor, which prescribes in five years; 4. Light penalties, in one year. The period therefore tracks the gravity of what was imposed, not the label of the offence. Note also that this article still names the death penalty. Republic Act No. 9346 (2006) prohibits the imposition of the death penalty in the Philippines; in its place the law imposes reclusión perpetua where the Code's nomenclature is used, or life imprisonment where it is not. Read the first paragraph subject to that prohibition.
The clock does not simply run in the fugitive's favour
This is the part that disappoints most people who ask the question. Prescription of a penalty is not a reward for staying hidden well. The Code does not treat the period as running quietly while the convict lives openly under his own name in the country; the running of the period is tied to evasion of the sentence and is interrupted when the convict surrenders, is captured, goes abroad, or commits another crime before the period expires. In practice that means an arrest, a voluntary surrender, or a fresh offence can reset what the person believed was nearly finished.
What this does and does not wipe out
Prescription of the penalty extinguishes criminal liability for that sentence. It does not erase the conviction from the record, and it does not by itself cancel civil liability — the indemnity, restitution or damages awarded in the same judgment follow their own rules and can still be pursued by the offended party. Nor does it help with a case that is still pending, or with warrants issued in other cases. If you are asking because a relative has an old standing judgment, the safest step is to have counsel examine the actual entry of judgment and commitment records rather than count years from memory. The dates on the papers, not the story, decide it.