To declare and believe in that there is no one worthy of worship but Allah (God) and Muhammad S is (the last) Rasul (Messenger) of Allah (God).
To offer Salah (Prayers) five times everyday.
To pay Zakah (Poor Due Charity) to the poor and the needy once a year.
To fast during the month of Ramadan every year.
Going to Hajj (Pilgrimage to the Ka'bah) once in one’s lifetime.
These five Pillars of Islam go far beyond the rituals they are associated with. Practicing and believing in these five Pillars of Islam, make a Muslim God fearing, kind, considerate, punctual, disciplined, sensitive, dutiful, patient, selfless, honest, faithful and believer in simple living.
These basic beliefs of Islam come as a package deal. One cannot pick and choose from this list. One has to believe in all of them.