El objetivo de este estudio fue determinar si en los pacientes fumadores de más de 20 cigarrillos al día había una incidencia más alta de pseudoartrosis que en los pacientes no fumadores. El estudio retrospectivo se efectuó en un grupo de 100 pacientes (50 fumadores y 50 no fumadores), intervenidos por problemas degenerativos del caquis mediante artrodesis instrumentada y posterolateral a nivel lumbosacro. Cincuenta y tres pacientes eran varones y 47 mujeres, con una edad media de 49+-10 años. Para determinar la incidencia de pseudoartrosis se valoraron las masas de fusión a los 6 y 24 meses de la intervención y la situación clínica del paciente. A siete de los 100 pacientes se les diagnosticó pseudoartrosis (2 no fumadores y 5 fumadores); los 93 restantes que no presentaron pseudoartrosis, 48 correspondían a pacientes no fumadores y 45 eran fumadores (p=0,24). No hemos podido demostrar la asociación entre consumo de tabaco y mayor índice de pseudoartrosis en pacientes intervenidos de artrodesis lumbosacra.The aim of this study was to determine whether smokers (more than 20 cigarettes per day) had higher rate of pseudoarthrosis than the non-smokers after lumbar fusion. A retrospective study was designed with 100 patients (50 smokers and 50 non-smokers). All the patients were operated on, by doing a posterolateral fusion with instrumentation (transpedicular fixation), due to degenerative pathology of the lumbar spine. Fifty-three patients were males and 47 were females, with an average age of 49+-10 years. To determinate pseudoarthrosis two types of evaluation were performed: Radiographic evaluation in plain radiographs at 6 and 24 months after surgery and clinical assessment. Seven out of 100 patients were diagnosed as pseudoarthrosis (2 non-smokers and 5 smokers) and, of the remaining 93 patients, 48 were non-smokers and 28 smokers (p=0.24). No evidence was found of correlation between cigarette smoking and a higher rate of pseudoarthrosis in patients with an instrumental arthrodesis of the lumbar spine.