Imams Bukhari and Muslim laid certain conditions for acceptance of Hadith and graded it accordingly. I want to know does Sheikh Al-albani followed any criteria for grading Hadith as Saheeh, Hasan, Daeef?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Shaykh Nasir-ud-Deen al-Albaani has his own methods of research (Ijtihaad), as it is the case with other scholars of Hadeeth who preceded him and who followed the established rules set for Hadeeth terminology. They did not invent something from their own selves.

Nevertheless, this does not contradict the fact that each one of those scholars has his own way of reasoning and preponderance. This fact is the reason beyond their discrepancies over the classification of the same Hadeeth, according to the rules and principles they received from their predecessors in relation to identifying the Saheeh (authentic), weak, and Hasan Hadeeth; and in the way of judging the chain of narration (Sanad).

The books of Hadeeth, old and modern, are abundant with these rules and principles which form the bases and guidelines for those who practice this science. Such books are: Muqaddimatu-Ibn As-Salah (authored by Ibn as-Salah), Alfiyyatul-Hadeeth by Al-Hafidh al-Iraqi, Alfiyyatul-Hadeeth by As-Suyooti, Tadreeb Ar-Raawi by As-Suyooti as well, and others.

One of the contemporary Hadeeth scholars, namely, ‘Amr ‘Abdul-Mun'im Saleem, wrote a book defending Al-Albaani. In this book, he enumerated some of the principles on which Shaykh Al-Albaani depended in judging the Ahadeeth.

Allah knows best.