The history of the death penalty was extensively discussed by the Supreme Court in People vs. Echegaray. As early 1886, capital punishment had entered the Philippine legal system through the old Penal Code, which was a modified version of the Spanish Penal Code of 1870. The Revised Penal Code, which was enforced on 1 January 1932, provided for the death penalty in specified crimes under specific circumstances. Under the Revised Penal Code, death is the penalty for the crimes of treason, correspondence with the enemy during times of war, qualified piracy, parricide, murder, infanticide, kidnapping, rape with homicide or with the use of deadly weapon or by two or more persons resulting in insanity, robbery with homicide, and arson resulting in death. The list of capital offenses lengthened as the legislature responded to the emergencies of the times. In 1941, Commonwealth Act (C.A.) No. 616 added espionage to the list. In the 1950s, at the height of the Huk rebellion, the government enacted Republic Act (R.A.) No. 1700, otherwise known as the Anti-Subversion Law, which carried the death penalty for leaders of the rebellion. From 1971 to 1972, more capital offenses were created by more laws, among them, the Anti-Hijacking Law, the Dangerous Drugs Act, and the Anti-Carnapping Law. During martial law, Presidential Decree (P.D.) No. 1866 was enacted penalizing with death, among others, crimes involving homicide committed with an unlicensed firearm. In the aftermath of the 1986 revolution that dismantled the Marcos regime and led to the nullification of the 1973 Constitution, a new constitution was drafted and ratified. The 1987 Constitution provides in Article III, Section 19 (1) that: Excessive fines shall not be imposed, nor cruel, degrading or inhuman punishment inflicted. Neither shall death penalty be imposed, unless, for compelling reasons involving heinous crimes, the Congress hereafter provides for it. Any death penalty already imposed shall be reduced to reclusion perpetua. Congress passed Republic Act No. 7659 (entitled "An Act to Impose the Death Penalty on Certain Heinous Crimes, Amending for that Purpose the Revised Penal Code, as Amended, Other Special Penal Laws, and for Other Purposes"), which took effect on 31 December 1993. 
This is extensively discussed in the case of People vs. Echegaray. (For editing) 
Abolition of death penalty
On 24 June 2006, President Gloria Macapagal-Arroyo signed into law Republic Act No. 9346, entitled "An Act Prohibiting the Imposition of Death Penalty in the Philippines". 
Effectivity of the new law
Section 5 of R.A. No. 9346 specifically provides that it shall take effect immediately after its publication in two national newspapers of general circulation. This is pursuant to Article 2 of the Civil Code which provides that laws shall take effect after 15 days following the completion of their publication either in the Official Gazette, or in a newspaper of general circulation in the Philippines, unless it is otherwise provided. R.A. No. 9346 was published in Malaya and Manila Times, two national newspapers of general circulation on 29 June 2006. Accordingly, R.A. No. 9346 took effect on 30 June 2006. 
As a result of the abolition of the death penalty, existing penalties for death were reduced to reclusion perpetua, within the possibility of parole. Here are illustrative cases: The case of People of the Philippines vs. Quiachon involves an accused who raped his 8-year old daughter, a deaf-mute. Under Article 266-B of the Revised Penal Code, the imposable penalty should have been death. With the abolition of the Death Penalty, however, the penalty was reduced to reclusion perpetua, without the possibility of parole under the Indeterminate Sentence Law. The case of People of the Philippines vs. Santos involves the rape of a 5-year old child. The accused...