This paper investigated the syntactic errors prevalent in Pakistani undergraduate studentsí written English. It also sought to outline the possible causes of these errors. The study employed content analysis by basing it on Corderís error analysis methodology to accomplish the research objectives. The study was conducted at a renowned private university. Participants for the study were those BS first year students who had obtained their higher secondary school certificate from Karachi Intermediate Examinations Board. The writing samples of eighty eight o students from this group were obtained. The corpus was then analyzed to discover the syntactic errors, and determine their frequency, types and causes. The major syntactic errors that emerged from the analysis were errorneous verb phrases, run-on sentences, semantically and syntactically ill-formed clauses due to literal translation from mother tongue, and faulty vocabulary respectively. An equal number of interlingual and intralingual errors were found. Studentsí inadequate competence, insufficient training, and limited exposure to the target language are considered to be the major causes behind the thence discovered errors.