**Exhibit 31.1****CERTIFICATIONS**I, Christian Itin, certify that:1. I have reviewed this Annual Report on Form 10-K, as amended by Amendment No. 1 to Form 10-K of Micromet, Inc.; 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to statea material fact necessary to make the statements made, in light of the circumstances under which such statementswere made, not misleading with respect to the period covered by this report; 3. Based on my knowledge, the financial statements, and other financial information included in this report,fairly present in all material respects the financial condition, results of operations and cash flows of theregistrant as of, and for, the periods presented in this report; 4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules13a-15(e) and 15d-15(e)) and internal controlover financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have: a) Designed such disclosure controls andprocedures, or caused such disclosure controlsand procedures to be designed under oursupervision, to ensure that materialinformation relating to the registrant,including its consolidated subsidiaries, ismade known to us by others within thoseentities, particularly during the period inwhich this report is being prepared;  b) Designed such internal control overfinancial reporting, or caused such internalcontrol over financial reporting to bedesigned under our supervision, to providereasonable assurance regarding the reliabilityof financial reporting and the preparation offinancial statements for external purposes inaccordance with generally accepted accountingprinciples;  c) Evaluated the effectiveness of theregistrant’s disclosure controls andprocedures and presented in this report ourconclusions about the effectiveness of thedisclosure controls and procedures, as of theend of the period covered by this report basedon such evaluation; and  d) Disclosed in this report any change inthe registrant’s internal control overfinancial reporting that occurred during theregistrant’s most recent fiscal quarter (theregistrant’s fourth fiscal quarter in the caseof an annual report) that has materiallyaffected, or is reasonably likely tomaterially affect, the registrant’s internalcontrol over financial reporting; and5. The registrant’s other certifying officer(s) and I havedisclosed, based on our most recent evaluation of internalcontrol over financial reporting, to the registrant’sauditors and the audit committee of registrant’s board ofdirectors (or persons performing the equivalent functions): a) All significant deficiencies and materialweaknesses in the design or operation of internalcontrol over financial reporting which are reasonablylikely to adversely affect the registrant’s abilityto record, process, summarize and report financialinformation; and  b) Any fraud, whether or not material, thatinvolves management or other employees who have asignificant role in the registrant’s internal controlover financial reporting.        Date: May 10, 2007 /s/ Christian Itin   Christian Itin                           Chief Executive Officer