**Exhibit 31.1**

**CERTIFICATION**

**Certification of Principal Executive and Financial Officer**

I, Laurence P. Birch, certify that:

1.                I havereviewed this annual report on Form 10-K of Aksys, Ltd.;

2.                Based onmy knowledge, this report does not contain any untrue statement of a materialfact or omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

3.                Based onmy knowledge, the financial statements, and other financial informationincluded in this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, andfor, the periods presented in this report;

4.                I amresponsible for establishing and maintaining disclosure controls and procedures(as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) andinternal control over financial reporting (as defined in Exchange Act Rules 13a-15(f)and 15d-15(f)) for the registrant and have:

a)                Designedsuch disclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

b)               Designedsuch internal control over financial reporting, or caused such internal controlover financial reporting to be designed under our supervision, to providereasonable assurance regarding the reliability of financial reporting and thepreparation of financial statements for external purposes in accordance withgenerally accepted accounting principles;

c)                Evaluatedthe effectiveness of the registrant’s disclosure controls and procedures andpresented in this report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period covered by thisreport based on such evaluation; and

d)               Disclosedin this report any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter thathas materially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and

5.                I havedisclosed, based on my most recent evaluation of internal control overfinancial reporting, to the registrant’s auditors and the audit committee ofthe registrant’s board of directors (or persons performing the equivalentfunctions):

a)                Allsignificant deficiencies and material weaknesses in the design or operation of internalcontrol over financial reporting which are reasonably likely to adverselyaffect the registrant’s ability to record, process, summarize and reportfinancial information; and

b)               Any fraud,whether or not material, that involves management or other employees who have asignificant role in the registrant’s internal control over financial reporting.
| Dated:  April 28, 2006 | By:    | /s/ LAURENCE P.  BIRCH                                     |
|-----------------------------|--------|-----------------------------------------------------------------|
|                        |   | Laurence P. Birch                                          |
|                        |   | President, Chief Executive Officer and Chief Financial  Officer |

 

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