Noise pollution is considered a stressful biological factor which can be hazardous for the health. Noise stress stimulates the hypothalamus-pituitaryadrenal axis (HPA). Acute and chronic stress increase such stress hormones as epinephrine, norepinephrine and cortisol. The purpose of this research is to determine the neurotransmitter levels. (dopamine (DA), norepinephrine (NE), serotonin (5-HT)) and microRNA-7a and -34c in serum and hypothalamus tissue of rats exposed to different powers of noise. To achieve this aim, 40 adult albino male rats were grouped in to 4 groups (10 rats each). Group I (GI) represented the control group and the test groups (GII, GIII and GIV) were exposed to different powers of noise at 85 dB, 100 dB and 135 dB respectively for 4 hours/day from 7a.m - 11a.m. for 15 days. The results of the research indicated that noise exposure led to a significant increase in serum level of NE in the tested groups and also increase in the relative expression of microRNA34c in hypothalamus tissue in (GIV) at 135 which can lead to activation of (fight-flight) response. Also led to significant reduction in levels of neurotransmitter DA in serum in the tested groups and reduction in neurotransmitter 5-HT levels in serum in (GIII) and (GIV) at 100 dB and 135 dB respectively and also reduction in the relative expression of microRNA-7a in hypothalamus tissue in (GIV) at 135dB. Noise exposure as a potent stressor caused a decrease in serum levels of neurotransmitters and a reduction in the relative expression of microRNA-7a in hypothalamus tissue that may lead to disorders in the function of HPA axis and the release of hormones