El Nino-Southern Oscillation (ENSO) has different impacts on seasonal agricultural systems in Ethiopia. In order to characterize effects of ENSO, this paper is therefore aimed to determine the impacts of various ENSO phases on cereal crop in Upper Awash Basin region of central Ethiopia. Here we used the rainfall data covering the period from 1980 to 2014 while selecting more reliable and continuous data from the Upper Awash Basin. Climatological pattern of rainfall and its variability, areal rainfall anomalies were evaluated with respect to global sea surface temperature. Multivariate statistical methods were employed to quantify relationship exist between regionalized rainfall index and Sea Surface Temperature anomalies (SSTa). The results of this study revealed that SSTa as recorded over Nino regions have strong signal in explaining regional rainfall variation than other ocean fields of the study area. In particular, Nino regions SSTa have negatively correlation with kiremt rainfall and vice versa in the case of belg rains. Computed weighted average rainfall for each homogenous zone of Upper Awash Basin and CDF with zonal cereal crop yield data, particularly for Teff, Wheat, Maize and Sorghum crops were analyzed. Risk analysis was computed against the ENSO-based approach using cumulative density function. The results showed that, preferable yield value and less crop risk were identified during non-ENSO years both by first and second stochastic dominance senses. Hence, non-ENSO phase is therefore found to be the best risk efficient set identified in Upper Awash Basin for crop productivity. In contrast, overall cereal crop yields were decreased in regionalized area three of Upper Awash Basin by 16% and 5.3% during El Nino and La Nina episodes, respectively. El Nino shocks are likely to cause a reduction in cereal crop production but it is relatively better than La Nina episodes for wheat crop production in regionalized area one of Upper Awash. So, having the information of ENSO phase in advance will improve agricultural practices such as selection of crop varieties and thus to maximize agricultural rain feed cereal crop productivity and minimize crop risk associated with fluctuation of seasonal rainfall under various ENSO phases. The results of this study would therefore be utilized by farmers and agricultural societies in the provision of alternate use of ENSO forecasts for further insightful decision, particularly on crop risk planning and management strategies.