Two mixtures (ethanol extract of taro plant leaves + roasted peanut, coriander oil, fresh coriander leaves, fresh zucchini fruit and cockroach faeces at ratio of 1:1:1:1:0.1, respectively, and ethanol extract of taro plant leaves + peppermint oil at ratio(1:1) were added to two commercial cockroach baits (Siko Biko and Ixon) and evaluated against a dults of the German cockroach, Blattella germanica (L.)under laboratory conditions. The efficacy of the tested baits was conducted through two different bioassays, no-choice and choice assays. The choice assay considered the effect of alternative food (white bread) on efficacy of the baits. The bioassays also considered the effects of ageing the baits for seven days on their effectiveness. All the assays were conducted in special glass arenas (45 × 25 × 25 cm). Results showed a significant increase in the attractiveness and efficacy of the improved baits against adult males and females. Baits mixed with the 1st mixture were significantly more efficient than baits mixed with the 2nd mixture. All tested baits attracted and killed more males than females. Ageing of the original and improved baits for seven days affected their attractiveness and efficacy, but the improved baits were more effective against the tested cockroaches than the original baits.