"Illallah" was Uddin's second album, which was released in May 2006 via IQRA Promotions and recorded in Denton Studios, Manchester and Digital Image Studios, Chesterfield. It was produced by Ahmad Hussain and Ahmir Hussain and illustrated by Rizwan Hussain of Digital Dawa. This album starts with him reciting Ar-Rahman; a Surah of the Quran, and various Islamic supplications. It featured a Bengali naat sending durood and salam upon Muhammad as well as an Urdu naat titled "Hain Nazar Mein". Uddin also collaborated with his student Mohammad Nobin Hussain on a remix of Al-Busiri's Al-Burda. The album also included a remastered version of "His Name is Muhammad" (from his previous album) with additional traditional lyrics in Bengali. The "99 Names of Allah" nasheed from his 2005 album was also included in this one. An official video was filmed for his title track "Illallah", written by his brother Faisal Uddin.