The aim of this preliminary study was to explore infant-mother attachment quality in a Dutch clinical sample of mothers with severe psychiatric disorder, with or without comorbid personality disorder. Thirty-two mothers were recruited through specialized secondary and tertiary outpatient clinics and mental health institutions. Maternal psychiatric and personality diagnoses were verified with structured clinical interviews during pregnancy. Maternal concurrent level of psychiatric symptoms was assessed by self-report and infant-mother attachment quality by observation in the Strange Situation Procedure at 14 months postpartum. In the full sample, almost half of the infants were classified as disorganized. All infants of mothers with a comorbid personality disorder were classified as either insecure or disorganized. Infants of mothers with a comorbid personality disorder had a significantly higher disorganization score than infants of mothers with a psychiatric disorder only. Continuous attachment security scores did not differ significantly between groups. In the full sample, continuous infant attachment security and disorganization score were not significantly correlated with the level of maternal concurrent psychiatric symptoms. Our exploratory findings suggest a specific link between maternal psychiatric and comorbid personality disorder and attachment disorganization. Moreover, chronicity of symptoms appears more relevant for attachment behaviors than the severity of concurrent psychiatric symptoms. Maternal personality disorder may have a strong formative impact on infant attachment security and disorganization, which warrants further research to inform clinical practice, in order to reduce the risk of intergenerational transmission of maternal psychopathology.