Currently, the classical, time-honored ileal conduit as well as the stoma1 continent urinary diversions have given way to the increasingly frequent use of replacement cystoplasty. In 1852 Simon performed the first continent urinary diversion in a form of ureterorectal anastomosis on a paitent with ectopia vesicae’ and in 1913 Lemoine reported the first true clinical use of a rectal bladder.2 This and most of the following attempts would be tempered by a high surgical mortality rate. In 1951 Couvelaire reported the first clinical use of bladder substitution, which was followed by only sporadic reports on this method.3 Since Kock et a1 in 1982 reported on their pioneering experience with the use of an ileal segment for the construction of a continent reservoir: we have witnessed an explosion of interest in continent urinary reconstructions via the cutaneous and urethrally anastomosed forms. The number of variants currently average more than 40 worldwide.4-7 Bladder replacement by a variety of small and large bowel segments has become a standard method of reestablishing voiding per urethra. Typical causes for replacement cystoplasty, defined as total cystectomy followed by reconstruction, are bladder carcinoma (the leading cause in adults), surgically unreparable bladder exstrophy, undiversion and a diseased vesicourethral unit requiring total cystectomy.8 TO date, radical cystectomy remains the most effective method of treatment for invasive bladder carcinoma. Despite all of the advances in chemotherapy and radiotherapy, these modalities have still not been demonstrated to be equivalent to surgery in terms of survival, local or regional control, or quality of life. Major refinements in anesthetic procedures, the advent of the modern antibiotic era, and recent advances in surgical, urodynamic and metabolic knowledge have significantly decreased mortality and morbidity rates associated with cystectomy and urinary reconstruction. h y patient undergoing radical cystectomy will be confronted with the option of selecting 1 of 3 types of definitive urinary diversion: 1) the ileal or colon conduit, 2) a cutaneous continent reservoir and 3) a neobladder for orthotopic voidingg Option 3, hitherto reserved exclusively for men, has recently been performed successfully following radical cystectomy in the female patient.10-15 An intensive quest is underway to develop an orthotopic continent reservoir, resembling the natural bladder as close as possible, that is technically acceptable to surgeons and the most socially acceptable to patients. At the same time, it is important that any such bladder replacement procedure protects the upper urinary tract. This event is even more rewarding since followup is hoped to match normal life expectancy. Some disillusionment with long-term results of the ileal conduit, particularly in children, added to economic factors, particularly in Some third world countries where the cost of ostomy appliances is prohibitive, have also been responsible for this swing. We review what we believe to be only some of the most commonly used neobladders (bladder replacement in situ with the native urethra) to date, covering the most salient technical features. Basic physical and mathematical principles related to morphology and functional behavior of neobladders will be followed by a brief discussion of the rationale for recommending this type of procedure to post-radical cystectomy patients, probably regardless of gender. However, it should always be kept in mind that “urinary continence must not be achieved to the detriment of renal function” as stated by Bricker more than 4 decades ago.16 This statement still remains valid to date.