The governor signed on the summary dissolving the assembly on the recommendations of Chief Minister Syed Qaim Ali Shah.
The dissolution of the Assembly comes two days after the Balochistan assembly was also dissolved.
The Sindh Assembly, with the coalition government headed by the Pakistan Peoples Party and Muttahida Qaumi Movement, was to complete its five year term on April 5.
Sources said the dissolution came since the ruling and opposition parties had agreed to a caretaker chief minister.