He founded the Orascom conglomerate, whose construction, telecommunications and tourism divisions are run by his three sons. Other companies he owns include Al-Ahram spirits (which was then bought by Heineken) and Orascom Holdings. Orascom is involved in tourism development, telecommunications, construction and other fields. Orascom Telecom Holdings is pioneer in the telecommunication section with operations in Egypt, the Gulf and North African regions. His latest telecommunication project was the acquisition the third largest Italian Wind Telecomunicazioni S.p.A.. The total value of the transaction was €12.138 billion. 51% of this deal was then transferred to Orascom Telecom. The transaction took place in June 2005.

Orascom Telecom has an estimated 20 million users in its operational countries (excluding Italy).

"The Guardian" has noted that Nadhmi Auchi had helped Orascom (which owns Djezzy GSM) gain a contract to set-up mobile phone networks in post-Saddam's Iraq .