This report documents AI’s concerns about the arrests of hundreds of members of opposition parties in Sindh, especially of the PPP, since the dismissal of the government of Benazir Bhutto in August 1990. Many were held for short periods only but several hundred were believed to remain imprisoned at the end of 1991. Patterns of political detention and the legislation under which opposition politicians were detained are analyzed and information is given about political developments in Sindh during 1990- 1992. A case study of the repeated detention of Pir Mazhar-ul-Haq is supplied. Unacknowledged detention, torture, ill-treament, arrest and harassment of families of opponents and possible political killings are also reported.