Is Sawm observed by a person abandoning Salaah considered valid?

Question: Some people observe Sawm (Fast) during Ramadaan, but they do not offer Salaah (Prayer). Will their Sawm be accepted by Allaah?

Answer: Allaah does not accept the Sawm of the people who abandon offering Salaah unless they turn to Allaah in repentance and start performing Salaah again. This is based on the Hadeeth in which the Prophet Muhammad (peace be upon him) said: What stands between a Muslim and disbelief is his abandonment of Prayer. Allaah does not accept any good deed by the Kaafir (disbeliever)… read more here.