In thi s study an attempt is made to explore the practical procedures in time domain univariaternBox-Jenkins methodology for modeling and forecasting monthly rai nfa ll in Tigray region. Inrnparticular, the study employs Seasonal Autoregressive Integrated Moving Average (SARIMA)rnmodel for monthly rain fall data collected by the Nat ional Meteoro logy Agency at Mekele stationrnfor the period from January 1975 to December 2009. Through the various model identification,rnestimation and diagnostics methods, we developed models that can adequately fit to the data.rnResidual analysis which is the important tool for diagnost ic checks shows that there was nornviolation of assumptions in relation to model adeq uacy. Further model selection was performedrnat the forecasting stage usi ng forecas ting accuracy methods based on the va lidation period. Thernpoint forecast results showed a very close match with the pattern of the actual data and betterrnforecast ing accuracy in the validation period. Accordingly, the more parsimonious SARIMA (0,rn0, I) x ( I, I, 4)12 model is found appropriate to describe the observed data. Therefore, the res ultsrnof the study indicate that SARIMA model of Box-Jenkins methodology allows in capturingrnmure complex description of the seasonality, autocorrelation structure and non- stationary of thernseries and appears to be reasonably good in forecast ing the monthly rainfall series. Futurernforecast results of the model show that there seems to be no trend of increasing or decreasingrnpattern over the period from January 20 I 0 to September 20 11 .rnKey words: Monthly rainfa ll, SARIMA, Box-Jenkins, Forecasting.