**Exhibit 31.1**

**CERTIFICATION**

          I, S. Scott Crump,certify that:

          1.          Ihave reviewed this annual report on Form 10-K of Stratasys, Inc. (the“registrant”);

          2.          Basedon my 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, not misleadingwith respect to the period covered by this report;

          3.          Basedon my 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 and forthe periods presented in this report;

          4.          Theregistrant’s other certifying officer and I are responsible forestablishing and maintaining disclosure controls and procedures (as defined inExchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financialreporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for theregistrant 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 consolidated subsidiaries,is made known to us by others within those entities, particularly during theperiod in which this report is being prepared;

                       (b)          Designed suchinternal control over financial reporting or caused such internal control overfinancial reporting to be designed under our supervision, to provide reasonableassurance regarding the reliability of financial reporting and the preparationof financial statements for external purposes in accordance with generallyaccepted accounting principles;

                       (c)          Evaluated theeffectiveness 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)          Disclosed in thisreport any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter(the registrant’s fourth fiscal quarter in the case of an annual report)that has materially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and

          5.          Theregistrant’s other certifying officer and I have disclosed, based on ourmost recent evaluation of internal control over financial reporting,, to theregistrant’s auditors and the audit committee of the registrant’sboard of directors (or persons performing the equivalent functions):

                       (a)          All significantdeficiencies and material weaknesses in the design or operation of internalcontrol over financial reporting which are reasonably likely to adversely affectthe registrant’s ability to record, process, summarize and report financialinformation; and

                       (b)          Any fraud,whether or not material, that involves management or other employees who have asignificant role in the registrant’s internal controls over financialreporting.

 

| Date: March 14, 2007 | /s/ S. SCOTT   CRUMP                  |
|----------------------|---------------------------------------|
|                 |                                       |
|                 | S. Scott Crump                        |
|                 | President and Chief Executive Officer |