Must one change one's first name when becoming Muslim?

No. Changing one's first name is not a condition for becoming Muslim: many companions, like Omar, Othman or Bilal, kept their pre-Islamic first names. The change is only recommended if the name carries a meaning contrary to Islam, for example the name of a worshipped deity, or a crude or negative meaning.

Otherwise, your first name is part of your identity and you can keep it.

Changing one's first name: what Islam says

No verse nor authentic hadith makes changing the first name a condition of entry into Islam. The shahada makes you a Muslim; your first name changes nothing to that reality.

The Prophet (peace be upon him) did change certain first names carrying a bad meaning among companions, but that targeted the meaning of the name, not a requirement of an "Arabic name": companions of the most diverse origins kept their first names when they were without defect.

First name and conversion: the example of the companions

Converted companions most often kept their first name: Omar remained Omar, Othman remained Othman, Bilal remained Bilal (son of Rabah), Salman the Persian remained Salman, Suhayb the Roman remained Suhayb. Islam spread over three continents without requiring anyone to leave their name: a Moroccan, an Indonesian or a Bosnian Muslim keeps first names proper to his language. Your first name is part of your history and your family: it is not an obstacle to your faith.

When changing one's first name is recommended

• The first name is that of a deity worshipped besides Allah (certain ancient Greek, Latin or Persian forms carry one).
• The first name has a bad or crude meaning in its original language.
• The first name humiliates you publicly or embarrasses you every day: the good name is the one that honours you.

In these cases, choose a name of beautiful meaning and replace the old one in current usage. There is no religious procedure: one chooses, one has oneself called that, that is all. On the administrative side, it depends on the laws of your country and has no religious incidence.

Choosing a Muslim name

If you decide to take a Muslim name, or if you will choose the name of your future children, Moustaqim's Muslim names module lists more than 2,400 names with their meaning, their variants and their origin, with dedicated selections for boys, girls and the names recommended in Islam.