One hundred consecutive patients, the majority suffering from bilateral chronic tension-type headache, investigated with lumbar puncture, were studied as to age, sex, body mass index, diagnosis, lumbar cerebrospinal fluid pressure, and signs of inflammation in the serum in relation to postlumbar puncture headache. Patients younger than 40 years of age were significantly more prone to develop postlumbar puncture headache than patients older than 40 years of age ( P =0.01). Sex, body mass index, cerebrospinal fluid pressure, and signs of inflammation in the serum were not related to the frequency of postlumbar puncture headache in the present study. Postlumbar puncture headache occurred significantly more often in patients with bilateral chronic tension-type headache than in patients with unilateral headache ( P =0.02) and in patients without headache ( P <0.01). In a regression analysis with age, sex, and chronic tension-type headaches, only bilateral headache contributed significantly to the prediction of postlumbar puncture headache ( P <0.01). Age did not contribute apart from the common variance with chronic tension-type headache/no chronic tension-type headache. The results may indicate that postlumbar puncture headache and chronic tension-type headache have etiologic mechanisms in common, mechanisms presumably localized intracranially rather than extracranially.