Background Syntax is defined as the system of rules for combining words into phrases and sentences.Patients with schizophrenia ,especially those with formal thought disorder(FTD), are considered to have language impairments at their lexical,semantic and discourse level.Syntax in these patients is usually considered to be preserved.Broca's aphasia is a disorder in which syntactic abilities of the patients are compromised.This study aims to find the syntactic errors in language comprehension in patients with formal thought disorder and those with Broca's aphasia. Method Twenty-six Malayalam sentences of varying word order and syntax were read out to the patients.Sentences were devoid of any real world meaning.This was done to prevent the subjects from using their knowledge in parsing the sentences.Examiner then asked questions regarding the information conveyed by the sentences.The purpose of the experiment was to assess the subject’s ability to understand ‘who did what to whom’ in the sentences. Results Ten patients with formal thought disorder(mean age=45.5 years) and 9 patients with Broca’s aphasia (mean age=47.1 years) participated in the study.Those with FTD had a mean test score of 15.4(SD=4.4),while those with Broca’s aphasia scored 12.5(SD=5.5).The difference was not statistically significant.Both groups did poorly with simple noun phrase pronouns, three place passive, three place cleft object, object-subject relative, object -object relative, passive conjoint agent, simple active reflexive and conjoined sentences.Both groups did well with noun phrase raising, optative, imperative, two place cleft object, two place active, three place active ,three reflexive expression, active conjoined theme ,simple active pronoun and truncate passive. Conclusion This study shows that syntax deficit in Broca’s aphasia is not absolute.For active ,imperative and optative sentences,syntax is fairly preserved in language comprehension.This may be relevant while communicating with these patients.While in schizophrenia, we have demonstrated that deficits in syntax occur in passive sentences and with pronouns.