Chronic kidney disease (CKD) treated by hemodialysis (HD) is a worldwide major public health problem. Its incidence is getting higher and higher, leading to an alarming social and economic impact. The survival of these patients is significantly low, especially during the first year of treatment. The purpose of our study was to identify the epidemiological and clinico-biological characteristics of patients at the HD initiation and to reveal the predictive factors of mortality at three months and one year of HD. This is a prospective, analytical, and descriptive study dealing with 229 patients with an end-stage renal disease (ESRD), followed up in the Nephrology Department of Charles Nicolle Hospital and La Rabta Hospital in Tunisia, that was started HD between January and June 2017. A multivariate logistic regression analysis allowed us to identify the independent predictors of mortality at three months and one year. The average age was 60.2 ± 15.3 years, with a gender ratio of 1.41. Seventy-eight percent of patients had more than two comorbidities, 59% had diabetes, and 88% had hypertension. Diabetic nephropathy was the leading etiology of kidney disease (48.9%), while 11% of nephropathies were of unknown etiology. Only 58% were early referred to a nephrologist. The average glomerular filtration rate at HD initiation was 6.06 ± 2.33 mL/min/1.73 m2. Hypocalcemia and hyperphosphatemia were noted, respectively, in 60.8% and 84.9% of cases. Anemia was objectified in 98.6% of cases. HD was started in an emergency in 56.8% of cases. One of the most urgent indications was acute pulmonary edema (APE) for 43.8% of patients. Only 10.5% of patients had functional arteriovenous fistula at the dialysis initiation. Patients were hemodialyzed one, two, or three sessions per week, respectively, in 23.2%, 26.6%, and 50.2% of cases. The crude mortality rate was 25% and 13% in, respectively, one year and three months of HD. On multivariate analysis, we identified heart failure and insufficient dialysis dose per week as predictive factors of mortality at the 1st year of HD. C-reactive protein more than 21 mg/L, insufficient dialysis per week, modified Charlson Comorbidity Index less than 6, and APE at the dialysis initiation were identified as predictive factors of three-month mortality. Despite the short period of study, this work revealed the alarming conditions of patients at HD initiation. This critical situation is due to the delay in CKD diagnosis, the late nephrologist referral, and the lack of preparation before HD initiation.