Back ground: Malnutrition accounts for almost half of the worlds all deaths in under 5 children. Worm infection is one of the immediate and commonest causes which affect the nutritional status of children. There by a deworming strategy was designed to improve the health of children. However, the effect of this strategy has not been well studied in rural Ethiopian setting. Objectives: To assess the effect of single dose deworming and associated factors on nutritional status of children aged 2- 5 years in Wonago Woreda, Gedeo zone, SNNPR, Ethiopia.

Methods: Community based uncontrolled before and after intervention study design was conducted in a three selected kebeles with a month apart. A total of 3324 children aged 2-5 years who were part of the deworming campaign were included in the study. Semi structured questioner was used for data collection and anthropometric measurements were computed using WHO Anthro nutritional software program. The difference of nutritional status before and after deworming intervention was computed using a paired sample T test. A univariabe and multivariable logistic regression model was computed to as determinants of the nutritional status.

Results: Data was collected from 3273 children aged 2-5 years with 98.5% response rate in the second spell of observation. One month after deworming weight was increased by 0.52 kg and height by 1.10 cm, the wasting proportion reduced by 15.4%, the stunting proportion reduced by 7.1% and the underweight proportion reduced by 16.7%. In the multivariable model, it was found that government employed fathers [OR=1.93(95%CI:1.08,3.46)], child age group 48-59month [OR=1.46(95%CI:1.01,2.09)], being a male child [OR=1.42(95%CI:1.07,1.88)], having diarrheal disease in past two week of  data collection [OR=0.39(95%CI:0.17,0.90)], and bathing frequency below two times per a week [OR=1.42(95%CI:1.03,1.96)] were significantly associated with  wasting. In another multivariable model, urban residence [OR=0.34(95%CI 0.19,0.59)], mothers with primary education [OR=0.71(95%CI:0.54,0.93)], house hold whose food source was purchasing [OR=2.86(95%CI:2.03,4.01)], greater monthly income [OR=0.76 (95%CI:0.61,0.95)], livestock ownership [OR=1.51(95%CI:1.18,1.93)], age of the child 36-47 months [OR=0.62(95%CI:0.45,0.85)], age of the child 48-59 months [OR=0.55 (95%CI: (0.39,0.79)], being male child [OR=1.88 (95%CI:1.53,2.31)], greater than two year birth interval from preceding child [OR=0.59(95%CI0.47,0.73)], and VIP type of latrine used [OR=0.32(95%CI:0.11,0.93)] found to be significantly associated with stunting. The third multivariable model found that family decision made by mothers only [OR=1.97(95%CI:1.04, 3.73) )], house hold whose food source was purchasing [OR=1.87(95%CI:1.27,2.75)], being male child [OR=1.61(95%CI:26, 2.06)], greater than two year birth interval from preceding child [OR=0.76 (95%CI: 0.58, 0.99)], and bathing frequency of child less  than two times per week [OR=1.38 (95%CI:1.03,1.85)]were among the determinants of underweight.

Conclusion: Children’s under nutrition is still a problem and after one dose of deworming weight and height was increased by 0.52kg  and 1.10 cm, the proportion of wasting, stunting, and underweight was reduced by 15.4%, 7.1%, and 16.7%, respectively. On top of deworming strategy, other important child, maternal, paternal or environmental related factors were significantly associated with children nutritional status warranting a close attention by policy makers and stakeholders in tier of deworming implementation.