Scientific inveStigAtionSStudy objectives: Recent findings suggest few differences in sleep continuity and quality between borderline personality disorder individuals (BPD-I) and good sleepers (GS). Nonetheless, BPD-I show marked discrepancies between subjective and objective sleep measures. The objective of this study was to document sleep in BPD-I, GS, and insomnia sufferers (paradoxical, Para-I; psychophysiological, Psy-I). Participants: Twelve BPD-I (mean age 33.3 years), 15 GS (mean age 34.1 years), 15 Para-I (mean age 41.1 years), and 15 Psy-I (mean age 36.6 years). Methods: Participants underwent 3 consecutive nights of polysomnography recordings. All participants completed a clinical interview and 2 weeks of sleep diaries. BPD-I received DIB-R assessment. Participants were not suffering from any other psychopathology and were drug free. Results: Subjectively, BPD-I and GS laboratory sleep reports were similar. However, Psy-I and Para-I took longer to fall asleep, were awake longer after sleep onset and during the night, slept less, and had lower sleep efficiency than both GS and BPD-I (p < 0.05). Objectively, BPD-I, Psy-I, and Para-I had longer sleep onset, shorter sleep time, and lower sleep efficiency on all 3 nights than GS (p < 0.05). Furthermore, BPD-I had more stage 4 (both in proportion and time) than Para-I on all 3 nights (p < 0.05). conclusion: Results suggest that BPD-I suffer from insomnia. While BDI-I reported feeling less refreshed upon awakening, they spent more time in stage 4 than other individuals. As BPD-I are very sensitive to loneliness and interpersonal stressors, laboratory settings might provide a secure context facilitating sleep.