Tetranychus truncatus is a serious mite pest of vegetable crops and ornamental plants in the state of Kerala, India. Heavy dependence on the synthetic acaricides for mite management has led to the development of resistance in mite populations, emphasizng the need for safer alternatives. Neoseiulus longispinosusof the family Phytoseiidae is a potential native predator of spider mites. The study aimed at evaluating the biocontrol efficacy of N. longispinosusagainst T. truncatus on marigold. A pot culture experiment was laid out in polyhouse in a Completely Randomised Block Design with five treatments, each replicated thrice. The treatments include: two releases of predator at 7 days’ interval (T1); release of predator followed by azadirachtin 1% at 3ml/L spray after 7 days (T2); azadirachtin 1% at 3ml/L spray followed by release of predator after 7 days (T3); two sprays of azadirachtin 1% at 3ml/L at 7 days interval (T4) and an untreated control (T5).One month old African marigold plants (Yellow Tall F1 hybrid) were uniformly infested with T. truncatus by clipping mite infested mulberry leaf bits (2x2 cm2) collected from laboratory culture. Three weeks after the release, the treatments were imposed, after recording the pre-treatment mite count. The predator was released at the predator: prey ratio of 1:35. Post treatment mite counts were recorded from 1x2 cm2 leaf area each from three leaves per plant, on 3, 5 and 7 days after first spray/release and on 3, 5, 7 and 10 days after the second release/ spraying. The data on mean mite population were subjected to square root transformation, followed by analysis of variance (ANOVA) using the online software, KAU-GRAPES. Seven days after the release of the predator, significant reduction in mite population was recorded in the treatments T1 (65.25%) and T2 (66.09%), while azadirachtin spray resulted in only 39.11(T3) and 28.82 per cent (T4) reduction. Ten days after the second release of the predator, significantly higher reduction of 97.10 per cent was achieved in T1 which was on par with T3 (93.89%), followed by T2 (82.69%). Ten days after the second application of azadirachtin (T4), mite population was reduced by 70.67 per cent. However, in the control treatment, mite population increased by 4.6 fold. The study concludes that N. longispinosus is a suitable biological control for the management of T. truncatus