Meiotic behavior and pollen morphology of Lippia alba. This study was carried out in the National University of Colombia UNAL and the International Center of Tropical Agriculture CIAT, to evaluate the meiosis in L. alba. The methodologies used were described by Dempsey (1993). Meiotic irregularities were observed such as precocious ascension of chromosomes, delayed ending of quiasmas, chromosome stickeness, tetradas with microcytes and polyads resulting in cromosome umbalance and production of inviable gametes. Meiotic index (MI) measured by the percentage of viable tetradas of microspores was relativily hight, indicating a razonable meiotic stability. Although the MI were of 77.3 %, pollen viability was up to 11.4%, which suggests that mutant genes could work post-meiosis. The size of pollen of L. alba was medium, with 28.0 μm of equatorial diameter and 26.9 μm of polar axis in equatorial view, oblate spheroidal, type of polar area is large and short aperture, triaperturate, tricolporate, zonoaperturate, pierced and tectate (optic microscopy and electronic microscopy of scanning EMS). Preliminary test showed very low viability and germination of seed.