Ruling on praying in Sufi mosques
Question

                In the suburb where I live there is a Masjid that belongs to Sufis and another smaller Masjid belongs to them as well. Is it permissible to pray in it?.
Praise be to Allah.
    Do not pray with these Sufis in their zawiyahs, and beware of 
    keeping company with them and mixing with them, lest you be affected by what 
    has affected them. Try to pray in the mosque of a congregation who seek to 
    follow the Sunnah and are keen to do so. 

    And Allaah is the Source of strength. May Allaah send 
    blessings and peace upon our Prophet Muhammad and his family and companions. 
    End quote. 

    Standing Committee for Academic Research and Issuing Fatwas 

    Shaykh ‘Abd al-‘Azeez ibn ‘Abd-Allaah ibn Baaz, Shaykh ‘Abd 
    al-Razaaq ‘Afeefi, Shaykh ‘Abd-Allaah ibn Ghadyaan, Shaykh ‘Abd-Allaah ibn Qa’ood