Experiments with weanling rabbits and Leghorn replacement pul­lets were condusted to determine the effect of dietary Yucca extract (YE) on atmospheric ammonia and on performance. Both experiments were conducted in identical rooms of 4.9 x 4.9m floor space. Rabbit ex­creta were accumulated on a plastic sheet with sawdust bedding; the chicks had 10cm sawdust fitter. Data were analyzed using SAS. In Expt. 1, New-Zealand White (NZW) weanling rabbits were assigned to 4 treat­ments: Control (C), C + 1 25mg (YE)/Kg diet, C+250mg YE/Kg and C+YE sprayed on excreta. There were 3 cage replicates per treatment, with 8 rabbits per cage. The trial period was 50 days. A second replicate was conducted with the excreta from the first replicate retained. Ammon:a (NH3) was measured 35cm above and below the cages with Drager diffu­sion tubes on days 7, 14, 21, 35, 40 and 50 in rep 1 and 1, 10 and 35 in rep 2. Average daily gain (ADG) and feed/gain for C, C+1 25 YE, C + 250 YE were : 27.7a, 4.55^a; 36.0^b ,3.66b ,36.7 b 3.57b for rep 1 and 27.72, 4.05°, 33.5^b, 3.72, 33.0b, 3.82^b for rep 2, respectively. Treat­ments showed significant at (P<0.05). NH3 levels (ppm) on day 50 (rep 1) for C, C+125 YE, C+250 YE above and below the cages were: 26, 30, 7, 13, 6, 9, respectively, while, rep 2 on day 35, NH3 levels were : 15, 24, 5, 5.5, 7.5, 8 respectively. In the chick trial, 500 Leghorn pullet day-old chicks per rep were used, with 2 treatments (C, C+1 25 mg YE/Kg) with 2 reps per treatment. NH3 was measured at weekly intervals for 6 weeks, at heights of 0.3, 0.9 and 1.5m. GroWth was assessed by weigh­ing 25 birds per pen at weekly intervals. After 6 weeks, body weight for C and C+YE were 349a and 395b, respectively (differences were signifi­cant at 5%•probability). NH3 levels (ppm) for C and C+YE were 21.3a and 6.7b, differences were highly significant (P<0.01). It is concluded that, dietary YE, under the experimental conditions, reduced atmospheric NH3 in poultry and rabbit houses, and increased growth rate.